Might I ask for some advice?

Is it possible that may people-- perhaps even the majority-- just don't have a driving passion?

I suggest reading this Paul Graham essay:

Do you think Shakespeare was gritting his teeth and diligently trying to write Great Literature? Of course not. He was having fun. That's why he's so good.

If you want to do good work, what you need is a great curiosity about a promising question. The critical moment for Einstein was when he looked at Maxwell's equations and said, what the hell is going on here?

It can take years to zero in on a productive question, because it can take years to figure out what a subject is really about....The way to get a big idea to appear in your head is not to hunt for big ideas, but to put in a lot of time on work that interests you, and in the process keep your mind open enough that a big idea can take roost

A sense of direction does not mean "forswearing experimentation". Without a direction you aren't going to get much accomplished. I spent years thrashing because I was (and am) interested in almost everything.

Besides the Paul Graham essay, you might want to read the Study Hacks series on deep procrastination, especially this one.

procrastination, in my experience, is not a character flaw, but instead evidence that you don’t have a believable plan for succeeding at what you’re trying to do.

Enjoyment isn't enough nor totally necessary (though it can make the work involved feel easier). The most important thing is to have a specific goal and a believable (by you) plan to achieve it.

I used to think that I was lazy in college too. I was "smart" so there's NO WAY the course load was too much for me, right?

Saying that I DON'T do well trying to handle a full course load seemed like saying that I was stupid. Especially since it's a better deal to take more classes (set tuition at 12+ credit hours is better deal than the per credit rate for less than 12 credit hours).

So it took me a looong time to admit that I should only be in 1-2 classes per quarter. In fact, I feel like I got MORE out of my money that way, since I could really focus on those 1-2 classes, and would end up learning WAY more in that subject than I would have if I took more classes, and retaining it better too, since I really took the time to internalize all the knowledge.

Of course, since you'd be spreading your time-to-complete out, you would need to work (in a job) more to compensate.

EDIT- Also, although right now "4 more years" or something seems like a long time, but relative to your total expected life span, it's not.

Is my not having direction a reasonable, youth-related status (is 22 that young?), or a sign that I've been doing something horribly wrong?

Very much possible. High school usually doesn't prepare you to really be able to identify your goals and capabilities, and therefore to choose a career. Usually it's at college that you have to confront with reality for the first time.

My lack of understanding in something is definitely correlated to how much, on a face-value level, I like something. It can't just be the online interfaces themselves.

In my personal experience it really takes a lot of time to completely make sense of the full picture of physics (and particle physics in particular). There are a few things that you can immediately understand, and other that make sense only when they come together to form a bigger puzzle. It's also perfectly natural to feel frustrated when you're stuck doing something you don't fully understand.

Does every potential physicist ask themselves these questions?

In my observations, at least half of them do. The other half either did a lot of previous research on the subject and are really convinced of what they're doing, or simply don't care.

All in all, what it looks like to me is that you're confronted with a difficult decision (basically, what to do for the rest of your life), and are confused by some amount of opposite evidence. I don't know you well enough to make an overall suggestion, but for the physics related part, it appears that you just realized that, well.. it's a tough subject. "Physics is a tough subject" is kind of a "mysterious answer": you don't really know what that means until you begin to study it. So, I'm not going to deny it: learning physics can at times be boring ad discouraging. But once everything "clicks" and fall into its place, it's a beautiful moment. If you enjoy those moments, then you will enjoy physics.

I hope I have been helpful.

I'm a graduate student, studying high energy particle physics. Research in particle physics is something I have wanted to do since I was 13 years old. Many people have dreams at that age, but as they grow older, they find that they didn't really understand what would be required of them, in one sense or another. This has not been my experience. The more science and mathematics that I learned, the more enthusiastic I became. I enjoy solving problems and working out equations; I enjoy programming simulations of physical systems; and I enjoy working in the lab, using equipment to get data, and then analyzing it. I do physics because I can keep doing it without getting bored, discouraged, etc. longer than I can do anything else.

That's not to say that there are never times when I get bored or discouraged, but those specific instances are uncommon enough that they haven't put me off the field as a whole. I certainly empathize with your distaste for MasteringPhysics (although it's not the worst online homework system that I've seen; that dubious distinction goes to WileyPlus). I was fortunate enough to attend an undergraduate program in which the physics majors did not have to deal with online systems, but I'm now a teaching assistant for a course which does use MasteringPhysics. As a TA, I can see the answers for my class' homework assignments, and even then I'm still sometimes mystified at what the system is doing.

It can be frustrating when you know you've worked out a problem correctly, but you get no credit from the online system because of some minute detail. The scoring often doesn't reflect your understanding. However, the actual act of working out the solutions to the problems should still be a little fun, at least sometimes. And, of course, academic physics is not all there is to physics: learning to do research and lab work is just as important, generally. If you're really not enjoying any of these things, physics may not be for you, and that's okay.

Lest I be accused of other-optimizing, I'm definitely not saying that everyone should hold out until they find something which is to them as physics is to me: an area in which they enjoy working, have some skill, and can make a living. That may just not be possible for some people, due to whatever combination of influences that controls their skills and what they find enjoyable, as well as the constraints imposed by economic feasibility. Many of us will have to go for two out of three on that list, at best. To be honest, whether or not I can make a long-term living in physics is still an open question. Much of my research contributions involve software and programming, since I'm pretty good at it (at least among physicists), so I could probably secure a software job without too much difficulty. However, I find physics more meaningful, and that gives me more drive and interest than I might have working on some arbitrary coding project. Tradeoffs like that are, for the time being, part of life (as long as basic resources remain scarce).

One parting note: don't get too down on yourself for having those days where you just want to vegetate with some entertainment. That happens to me, too. It's okay to take some time to ourselves now and again; trying to be productive all the time will just lead to burning out.

You managed to have a section titled "The Actual Problem" without ever discussing the actual problem. Starting with a few detailed examples of an "endeavor [that] ends in this way" would be helpful. Analyzing what (ostensibly) led you to abandoning each individual endeavor might help deduce a pattern and potentially some underlying reasons. Why did you drop out of philosophy? What is an example of a physical concept that led you to dislike the underlying mathematics?

As for majoring in Physics from a practical point of view, it is only worth it if you can't get enough of it. Computing/Engineering/Commerce/Finance provides a much better bang for the buck (or buck for the bang, as the case may be).

Facts that need to be cleared first: (1) you are 22, (2) "passion" is a meme imported from the tech industry.

You shouldn't have a sense of direction at 22. If you do, you're doing it wrong; it means forswearing experimentation, which is a huge net positive endeavor at that age.

People usually develop a sense of direction because of path dependence. Since you are not in a professional major, dependence is weak. The down economy, with its ebb of opportunity and grim signals, worsens any confusion. If you feel you are even more confused than you should be, that's probably the reason.

The passion thing is just what techies talk about to thump their chests. It means whatever the speaker needs it to, just ignore it.

I suffer from the same problem and this topic have been talked about quite a bit before, though I don't think there is an accepted solution to the problem posted yet.

As I understand it, this confusion is not at all due to the activity being chosen, but skeptical methods exposing the illusion of coherence of the mind. To think harder would point to the traditional sense of self being more a flawed map then some physical level construct however it does not suggest a comfortable, stable alternative in which to organize mental processes.

On the short term, one thing that has been on my mind is how to merge the very counterintuitive empirical, outside view of the self with the inside view and not run into ineffective introspective loops,