I've noticed a recent trend of gas stations here in the US starting to have upscale convenience stores attached to them, with more upscale products, clean bathrooms, actual quality food, made to order sandwich counters, etc.
As for Japan, the only convenience store I went into in Tokyo, I got freaked out when all the employees stopped and greeted me in unison. I can see it was meant to be welcoming, but it made me very uncomfortable and I left.