Book content question?

Ok, so I'm a girl who has never experienced true embarrassment. And for a book I'm writing, this one girl is jealous of another girl and she gets back at her by doing small things (3 times) and then one big thing. So if you could give me three little things that bug somebody (like wiping their toothbrush in the toilet or something) and then one big, that would be great. Thanks so much.