The clarinet section leader in my school's band has crossed the line with me.
Story goes like this: The only reason she's the section leader is because Joey, the best candidate, was made ineligible because his French teacher turned into a bitch at the beginning of the second semester and he failed one of the 6 weeks. None of us really thought we needed a section leader except for the village idiot, Shannon. As such, she tried out and won because no one else did.
She's been a shitty section leader all year, but I wasn't completely bothered by it because she wasn't doing anything that personally pissed me off. That changed this morning.
She got pissed at me because I didn't always flip to whatever piece of music we were playing at the time because I had memorized it. I can understand some of the shit she's done in the past, but I draw the line at her getting pissed at me for not following a nonexistent rule.