I also find makeup counters incredibly intimidating and not very effective. The salesperson's makeup style often doesn't match my taste, and it feels a bit dated (except MAC - I would like the MAC counter except I am sensitive to ~everything they make).
Sephora changed everything for me. They really don't mind you going in and browsing and trying everything. No hard sell. So I decided to figure out makeup in my mid thirties. I found the Sephora salespeople who seemed to have low-key taste and asked for help with one element at a time.
The other spectacular thing is Sephora's return policy and the ease of getting samples. Like Gigi, I have a lot of sensitivities. So I will never buy something the day I first try it. I go to Sephora, try the product, wear it all day, and come back the next day to buy it if it didn't cause any discomfort. Revolutionary. And if it doesn't work out, I can always return it.
Thinking about it, I'm guessing Sephora staff don't work on commission?
I know Sephora is mostly found in big cities and fancy malls. The one I go to is really busy, which probably helps - the salespeople can't hover over me if there are a thousand teenagers swarming the store. Ulta has more locations I think, so maybe that's a good alternative for people without Sephora nearby?