I'm struck by your saying that their other customers are friendly too. That's a huge point that I hadn't thought about consciously. But of course, I'm going to feel more at home where the other customers are more like me. In the bad-fit bike shop I wandered into and wound up buying Clyde, my current bike, I always feel like a huge clumsy in-the-way thing and the other customers are allowing me to speak to the mechanic with a sort of embarrassed politeness, the way one might if a mentally disabled person were ahead of them in the queue at the bank or something.

Hah! This is a great insight. I'm going to the place where the other customers smile at me and talk bikes.