When you respond with..
k/thanks/whatever/etc: pisses me off
ok/mhm/sure/etc: pisses me off even more.
or actually when you just respond with one word. It angers me, that’s like ending the conversation right there.

I don’t want to talk to you anyways! D:

I’ve grown to not like you very much. But yknow, since you’re like the best of friends with someone that I feel in particular doesn’t really care about myself, I should just be nice to you. Oh and you’re with soandso so I guess I have to be nice. But in the end of the day, I really don’t like you, I don’t like you at all to the point I can possibly say I hate you with a passion. But woah I’m going overboard there.