Why do you dislike X language/framework/library?

This has nothing to do with performance, right tool for the right job or what have you.

For one reason or another there exist a "software technology" that you simply do not like.

Who cares what Y fanboy says, or what X fangirl thinks? maybe it looked at you funny... but if you've got a legitimate, pragmatic reason that's ok too!

Tell me YC... What is it, and why?

Bonus points: how do you respond when someone within shouting range has the bright idea to use this technology that you loathe?