I can generally do this, so I will try to say something about it :-)

My hunch for how I got the power is that I had numerous "terrible jobs" that helped me pay for college, and which I look back on as having sometimes been more educational than many of my "more forgettable" classes.  One of these jobs involved door-to-door non-profit donation solicitation. I was selling almost literally nothing except "getting to feel good about the environment", which is quite a thing to try to sell.

In practice I listened to lots of people explain why they weren't donating, and my manager didn't like that I propagated many of the questions back to him, rather than propagating lots of no-strings-money back to him, and eventually it was pretty clear that I wasn't going to swiftly hit "the higher quotas (in excess of guaranteed daily pay) expected from experienced donation solicitors" and was let go. The experience gives me a foundation of empathy for the people doing the sales.

Personally I mostly don't even mind if people knock on my door and try to sell me something, unless they do it at weird hours in ways that breaks my time into smaller parts when I was using a long stretch to do a non-trivial piece of thinking.

Granting that I allow the break in my time and even opened the door...

...usually the sales pitch is from a normal person with high sales skill, and generally I'm friendly and explain that I did door-to-door stuff myself, and I admire something about their technique, and I make it clear that I will almost certainly not buy.

Really, the only way I would buy from a normal person is if they taught me so much about the overall market and product that I'd feel guilty not compensating them for the educational value of the sales effort (which is the same moral principle which caused me to buy things from Amazon for many years, for products I couldn't have discovered any other way but which were cheaper on other websites with worse metadata), but this feeling of reciprocal exchange almost certainly can't be the case for whatever will be said by a random door-to-door seller who doesn't bring a multi-media presentation with a bibliography (or something).

My commensurate skill and "seeing of them as an OK person with a sometimes icky job" comes through pretty quickly, and then it becomes very clear to them that they shouldn't hang out too long for economic reasons... but then like 50% of the time they seem full of relief to be treated like a human, by a human, who has escaped "object-object relational sadness" and I actually kind of like these moments, and they seem to as well, and then the moment ends and we get go back to our respective ways of being busy :-)

A couple times I've offered them some lemonade or whatever, and once (this was a whole family thing though, with my parents as the instigators) it got as far as inviting some Mormon boys back for dinner and theology, but we didn't crack them as far as I'm aware.  All of their pitches were designed to switch people away from being babptists or catholics or 7th day adventists or whatever. Our pitch that there's a positive absence of archaeological evidence for Jospeh Smight's claims of a lost tribe of Israel in north america seemed to roll off of them like water from a duck's back.

The only exception to "a generally positive experience" with sales folk is when like... like... a developmentally disabled people shows up on my door, which is just... uughhh(!)... so complicated..  but then... in those cases often I just donate money to them directly as an act of interpersonal charity? And if they have enough pride/ego/whatever to refuse such a donation then sometimes I fall back buying something I don't need so that developmentally disabled people can have jobs they are proud of? It's like a choice between two kinds of guilt, and I don't have a good way of resolving it right now.

I think I'm not alone in having a "pity gap" and I think girlscout cookie sales seem to have successfully weaponized this gap in many people's defenses (modulo by asking for a slightly different kind of unique moral toleration for a different kind of "objectively charity-worthy" person) and there are some interesting conversational gambits possible here <3

One thing is that the company sales system seems to know that people like me might try to just donate directly to the girl scouts, and sometimes they manage to inject "rules against just taking donation money" and I think the cookie manufacturers (understandably(?) in the valid(?) pursuit of money) want this rule...

...but I feel like the girlscout troops themselves "abstractly should not want this rule"?? But some of them have it. Which is weird.

One time a mom of a girlscout gave me an explanation about how the educational value to the cookie selling project included inculcating a coherent and pragmatically viable work ethic in the kids via baby steps that could launch higher level things that are less fake... which... was a good point? Maybe?

Certainly my ~4 weeks in a door-to-door sales program was retrospectively-positively-formative for me.

I think maybe it might still be a "rationalist thing" to try CFAR-style COmfort Zone Expansions (COZ-Es) [LW · GW]? I'm not sure about the details there, but I DO think that some important "mental powers" might be available some limited experience in professional sales in a way that is good for normal adults in a normal modern society to have.

Roughly: sales isn't illegal, so defense is necessary, so learning the basics of attacking is valid and potentially even wholesome (EG as with the girlscouts) <3

perhaps we should offer people some training for situations like this.

The salespeople have training for it.  But there's a big assymetry involved - it pays for salespeople to get better at selling, so the training is (to the extent it's effective) self-funding.  Victims don't get paid, so it's hard to justify the cost/expense of training.   This is especially true for this type of training, which consists of "let's practice getting past the discomfort by experiencing it multiple times and remembering to always focus on our goal".

Which highlights the main assymetry.  The salesperson HAS a goal - they want to sell something.  The victim does NOT have a clear goal - they want to feel good about themselves on many dimensions (politeness, providing for family, getting good deals, etc.), and haven't thought about what they want from THIS interaction.  

One of the most basic general sales scripts is this: After a purchase has been made, say "Great. Today only and for people who have already bought from us, we have 25% off our XXX, if you just check catalogue page 19."

Whether they buy or not, you follow with, "We also have 25% off our XXY, if you have a look here."

And on and on.

The script is simply not to go away, keep asking for more sales, until the buyer breaks social decorum by being literally rude and just saying (some version of), "Stop. I am done. This conversation is over."

Seems to me like a question of "how much do you forgive", which people mostly choose instinctively. Forgive too little, and then you needlessly escalate unintended mistakes. Forgive too much, and then some people will exploit you.

In theory, the best solution would be to find out exactly what happened, and react accordingly. But of course people will lie about this. Another strategy is to be charitable first, but then put abusers on a blacklist. Which doesn't work when you interact with strangers. Yet another strategy is to "trust but verify" the people you know, and automatically mistrust strangers. That also has some costs, plus the problem of how much interaction is needed to reclassify someone from a stranger to an acquaintance. (And some salesmen have a way to hack this algorithm, by insisting that you introduce them to your friends, which gives them fake "friend of a friend" credentials.)

Essentially, this is the thing I hate about salesmen and similar folks: A certain degree of forgiveness is socially useful, it reduces the conflicts, allows to overcome misunderstandings, etc. But there are people who burn the commons for fun and profit.

Sure. I have an opposite problem, of ending the interaction with at least the minimum of politeness instead of anger or utter contempt. I typically manage it, though. (though I don't actually have to deal with door-to-door salesmen ever, and phone sales extremely rarely. So it's more people who approach me on the street to try and sell stuff or ask for money).

Nevertheless, this has been interesting to consider. While I'm not vulnerable to door-to-door sales, I recently noticed I may be vulnerable to less obvious variants of the same kind of manipulation. I feel this is an example of a general pattern in social interactions (or, say, work relations).

You feel that the true reason to say no is impolite/unacceptable to say.
You say something that sounds polite/reasonable instead, even if that is not your true reason (though it may be part of the reason).
You have now pseudo-committed to acting like it is your actual reason to say no. This has created an attack surface that can be exploited.