I want to leave my gf on New Year's
Why that date?
I want to be with someone who is more fun.
I understand that you are bored with your girlfriend. However, you should really try to discuss your feelings with her instead of just abruptly ending the relationship. Otherwise, she may feel animosity towards you afterwards.
Nah, I'm going to just dump her on New Year's.
If your mind is truly made up, then I guess I can't change it, but I hope that I can talk you out of using New Year's celebrations to dump your girlfriend. The holiday is supposed to be about fun and hope for the future, and you shouldn't ruin it for her. If you have to break up with her, do it now instead of waiting.