The fact that I feel obligated to reply to pointless everyday shit like "Have a good day" with another equally pointless statement like "Yeah, you too".
Usually both parties state these things glumly, so the words just feel empty and meaningless, and even if someone sounds cheerful, I end up hating them for either being fake, or because I'm having a shitty day (that the cut & paste words of a stranger would do nothing to improve).
Essentially, I'm pissed off at pointless lip flapping.
My belated new years resolution is to remain silent, and ignore this pointless crap when it's directed at me.