A stuck up person is someone who waits on you at the bakery, cafe, or other place but when you pass right by them in the coffee shop, on the street or other place, they won't look at you, they won't acknowledge your presence and they certainly won't speak even a "hi" to you.
The stuck up girl who works in the bakery and who's waited on my son and I about a thousand times. I noticed her not being friendly to my son and I right from the get-go. After a month or so I got sick of it and mentioned it to the manager right in front of this worker. After that she starts being friendlier and I even chat with her a little at times. But how come I wasn't surprised when we saw her at the coffee shop and she totally ignores us. I think she's terrible; I can't stand the sight of her.