When I was about to graduate from Uni, I did a string of practice interviews for places who were interviewing new graduates )or otherwise). I applied to all kinds of places (including in blue-collar industries) just to feel comfortable with people asking you questions all sorts of questions.

I recall the blue collar employers questioning me about my choice to interview as they saw me a s "flight risk" that I'd find it beneath me or something --having been going thru Uni, or that I might not fit in with the rest of the shop workers.

Basically, interviewers want some assurance of some type you will fit in, whether you'll be able to blend in with the rest of the employees -in the blue collar places, that I might fit in with a less polished crowd and whether one might find it fulfilling.