I used to be approached a lot, maybe I now try to avoid eye contact with some people who seem to creep slowly sideways towards the car hoping you don't notice, or maybe they're looking for an invitation to talk. Or maybe I'm confusing it with some other carparking activity?
If you do approach someone at a supercharger I'd suggest not asking "How fast does it charge?" or "how far does it go?" as your first question hoping its an icebreaker!
I'd probably start with something like "Hi, I'm close to buying a Model 3 but would love to ask a few specific questions if you have a minute...". The more knowledge you have before you ask, the better the reception, at least thats what I'd like. You can always get around to the range type questions but again I'd couch that more specifically - "I have to drive up to Bristol a couple of times a month, it's about 100 miles each way, a bit apprehensive doing it in winter.." type of thing. You may also find owners have very different levels of knowledge so don't necessarily be put off by anything you hear.
There are a number of good resources that can provide background reading such as this website (although its not really set up for structured reading but now the thread exists, no hard in asking a question or 2 if you can't find it on the search), I personally really like the Tesla-info website as that is very structured and knowledgable. I'm much less of a fan of some of the youtube channels, and I actually find some of those can actually misleading. I see youtube as useful for seeing how many banana boxes can be fitted into a car but when looking at specs and range, I'd forget it. Gazing at a spreadsheets is far too geeky for what you need. You also seem to get lots of buyer remorse or confirmation bias on youtube - so either ultra critical or ultra positive - and sometimes both from the same person over time about the same car .
