I think it is important to distinguish hate from anger. They often go hand in hand as one induces the other but anger is fleeting. It is an emotion connected to adrenalin, aggression and agitation. It makes you move.
Hate, on the other hand, is more intellectual. It makes you think, it makes you plot. The guy who really hated to get wet invented the umbrella. Those who were just angry, complained about it.
When you really want to change something and are willing to do something about it after your anger has gone, then you hate. That hate will keep you going and focused and it will keep your memory sharp.
I'm just too lazy to hate anything.
Some absolutely excellent points here...