On some level, you do need a motivation, so it would be foolish to say that anger is a bad reason to do things. I would certainly never tell you to do only things you are indifferent about.

On another level, though, doing things out of strong anger causes you to ignore evidence, think short term, ignore collateral damage, etc. just as much as doing things because they make you happy does. You think that describing the society that will make you feel happy makes people run screaming? Describing the society that would alleviate your anger will make people run screaming too--in fact it already has made people run screaming in this very thread.

Or at least, it has a bad track record in the real world. Look at the things that people have done because they are really angry about terrorism.