Waiting tables at the tail end of high school and throughout college really boosted my intrapersonal skills. I have no problem interacting with most anyone and can usually pick up on cues that go beyond what the person is saying. I work in engineering at a fortune 500 now it's really amusing how bad a decent swath of employees are at getting their point across, understanding what someone else is trying to tell them, and reading the room.

That said, I had a stint in retail. Waiting tables was more stress, but the people were generally quite a bit nicer.