Time Inconsistency

There are things I really don't like doing, yet I know I should. And since I know I should, I schedule them well in advance in a way that it is basically impossible to call them off. I don't really mind - it is far away, so it does not seem to be that bad. But as it is approaching, I realize how unhappy I'm doing that particular stuff. Yet, I cannot call it off, so I keep thinking "I won't do it next time". But I know I will...