I have hated a lot of things and people(more specifically the ways people act) but there is such a thing as civility while interacting with them or in groups. Always feel free to express your opinions( for some, preferably while you are alone) Zero Tolerance is an easy way out of dealing with issues that go much deeper. Hate speech must be protected at all costs, if we lose our right to express our opinions then we have lost freedom :)
Civility for Peace!
Hate cannot be stopped we don't live long enough to all learn from our mistakes and those we hurt along the way to learning peace fuel the flames of hate to continue the cycle.
A good way to help keep a open mindset about someone who has 'earned' your hate at one point is this scenario of mental reflection:
1. You 'hate' someone because of something they did or said.
2. Whenever you are around them you are prejudice to them because of past event(s)
Now, if you put your younger self in that persons place...
1. You hated how dorky you looked when you were 5 years younger, or if you had braces, etc
2. You don't think you are as bad as you were then do you? You've grown, changed things, etc and not the same person.
So that means that the person in question gets a new opportunity to redeem themselves each time you are around them. Now don't expect much :P But its a perspective shift for yourself to make the time more bearable. Sometimes a person doing something you hate can be comforting because its reliable, like my Uncle always being 2 hours late on Xmas each year because he is shopping at the last minute. It used to bother me cause I wanted to open presents, but now I find myself happily joking around about when he will show up :)
So bottom line, Hate's not such a bad guy. Its a blanket word thats just easier to say than explain with a thoughtful sentence about how you feel.