What steep learning curve do you wish you'd climbed sooner?

Linux/Unix & their associated command line stuff. The number of times it's come in handy to be able to SSH into a machine that's way over there and do stuff is immense. Sadly I waited till Uni to learn, and I wonder where I'd be now if I'd internalised these concepts by the age of 15.

Need to log something you've just done? Redirect the output into a file. Boom. No longer do you have to find the bit of software that does everything, you just need programs that do simple stuff you can repurpose*.

Reading FOLDOC a bit to get the history was handy too. Thinking of computers as CPUs attached to teletypewriters, with all that fancy graphics stuff as optional explains a lot of how current software ended up the way it is.

*Totally not advocating mainstream computing for every user end up like this, btw. (Linux still makes me cry on a regular basis) Just that being able to drop to a command line and chain together commands or write scripts is so powerful that it's a game changer.

Vicarious regrets: Negotiating salary. Basic investing. Budgeting well below ones means. Sampling many subjects and careers to see how they fit.

Personal regrets: Ability to make good impressions on non-nerds (e.g. dressing well). Meeting lots of people.

Somatics. Interacting with your own body in a decent manner brings all sorts of advantages. If I would go back 20 years and meet my younger self that's the most important thing.

Formulating knowledge for SRS like Anki.

Social skills.

This question is kind of weird, in the sense that what I really wish is that I had climbed some shallow (big wins with not too much effort) learning curves earlier. In lots of domains, an 80/20 rule applies, where you get 80% of the benefit with the first 20% of the effort expended.

Programming. Writing essays. Learning an instrument.

Spotting and establishing connections with Gervais's Sociopaths. If I would have done this in university I would have a more useful network.

Doing CBT - not that may not be aplicable to people with better mental health

Steep?

String Theory and related math. Math is not my strongest suit, so taking the same courses a decade earlier would have been much easier and more productive.

Some musical education. I have no relative pitch to speak of (or at least a gross mismatch between identification and reproduction), but early training would have at least enabled me to carry a tune without being horribly off key 100% of the time. It sucks that I can't even sing to myself without cringing.

Hm. I thought a bit. Looked through the list. Thougt a bit more and concluded: I'm quite happy with my learning curve,

Only after looking thru the comments did I consider Investing. Advanced Investing actually. That would have been handy not only because of the money but also for more interesting job opportunities. Problem is only that I'm not clear how I could have had a path to that knowledge.

I'm quite happy that women and style knowledge are placed so late in my life. The mastering of these can eat insubordinate amounts of time and effort and cannibalize other areas.

I', very happy that math and the sciences came first (and deep) and have made learning all the other areas much easier.

See also http://c2.com/cgi/wiki?BreadthFirstLearning an old wiki page about how people acquire knowledge.

The hows and whys of refactoring and DRY. How and why to achieve proper separation of concerns (I still have lots to learn there).

Social protocols, especially around initiating and maintaining friendships and other levels of relationships. Being empathetic.

Statistics. I took it in High school, but it was so poorly taught that I learned almost nothing from it. Now I use statistics every day.

Scripting Languages. I learned Java in High School and rode that knowledge all the way through my CS degree. But when I got a job as a software engineer, Java was among the worst languages available for solving the type of problems with which I was dealing. Looking back at my old code, I could have saved hundreds of hours if I had learned Python instead of Java.

Related, curves I haven't climbed but wish I could/would/intended to:

A European foreign language. I dabbled in a variety of languages in school and settled on Chinese, wasting many years and having little to show for it. If it had been an Alphabetic language (and better yet, a Latin-alphabet language), I'd have a much higher level of proficiency.

A Martial Art. I love the martial arts, but I've never been able to devote myself to any one of them.

I'm tempted to say "social interaction", but I'm not entirely sure it would be honest. I wish I knew it now, but at the time I wish I had learned it, the measure of my interest in people was an imaginary number.

Playing an Instrument for sure (I'm a classically trained Flautist) Photoshop/adobe programs Business Myself and my own core distortions Writing (I started that journey when I was 12 and am just coming into my own) Design

I should probably get better at Math but I don't really need it and I don't code or program and I'm sure there are people that think I should do that.

Most things that I have taken on I have put in effort and gotten a result as well as manifesting the right people to help me.

I do not like "steep learning curve" the way people use it. It raises my probability estimate that person using it has done no study of learning. This reduces my probability estimate that they have sound insight about learning.

Sometimes I work with learning curves for machine learning or human learning. These curves are plots of a measure of learning (say, correct score, or number of mistakes) versus time or number of trials or number of training examples or number of iterations. When topic is hard, curve is shallow! It takes more learning to improve score or reduce mistakes. Steep learning curve means topic is easy. Mastery comes with very few repeats or little time or little data.

Does anyone know why so many use it wrong, to mean topic is hard and progress is slow? I believe Wikipedia article is right and "learning curves" must come from scientific study. How did meaning get reversed? Wikipedia article says "Arguably, the common English use is due to metaphorical interpretation of the curve as a hill to climb." but has no citation.