What are some memorable customer service moments from film?

I’m taking a customer service class as part of preparation for my AAT in Pharmacy Tech. The first night, my teacher showed the clip from Meet the Parents when Ben Stilller is trying to get on the plane and the lady at the desk won’t let him board until she’s called his row. She said she’d have more like that.

I get to pick one of the “10 most unwanted” types of people to deal with for an end-of-term presentation and I wanted to put some video in it. What are some good movies I could look to?