Because the world has hurt them deeply, so much they Hate all that it contains. It's sad, but true. Which drives them into a Life of fear, which is the core of all anger.

Because they don't realize it's a choice they are making.

a life full of hatred would mean that you didn't have to worry about being hurt. Hatred disconnects you from the world in a way. If that is what they want, thats why the person chooses that. Like some of the others said, it may not be by choice. But I think if you can push everyone away, who is going to be there to hurt you?

Hatred makes people feel powerful. There is so much to be angry about anymore that it's like fule to those who are unhappy. It is so much easier be hateful rather then to feel weak and emotionaly out of control.

because they hate themself ...
ive known a few and when i finally figured out why they were so hateful it stopped hurting me so badly ...

Ego protection.

Anger is a way of avoiding either a) hurt or b) fear.

I don't know who you're categorizing this way, but, it applies to everyone, so....

It almost seems for some that they were just born that way, some have it instilled in them by their parents.

I feel some people don't choose it, it is engrained in them, from the beginning, by their parents, and environment....

But, for those who actually do choose it, I think they think so little of themselves, that they have to do something to get noticed....to make them feel like they even exist.

Fear.

Who says they choose? Some do, maybe. Most are probably traumatized from experiences in their past.

I agree with Insanely.

All of the above; plus, for some people, it's all they have.

I lived this life at one time. There were reasons aplenty. It's a form of self preservation after so long. And we try to not embrace the fear and all that took us there, but it's a struggle even for the best of us.

Its so easy to be angry when your already unhappy,
you could be unhappy for several different reasons.. your job, your friends (or lack there of) your boyfriend, your family, yourself.

i find that i am more often than not, very depressed, and that i am very angry, and very mean to people that dont deserve it.

Anger is easy. Why bother understanding something when you can just hate it away. It's the fuel of all of mankind's darkest emotions.

Not having hatred in your heart is the hardest thing.

TYPE 1, The narcissist coward. (These are the type of parents who always make them think they are right…i.e if they get in a fight at school, they always get all puffed up and angry cause it’s THEIR kid and THEIR kid is a faultless creature ;) ) Because they prefer to believe everybody else is wronging them than to own their own part in things.

Owning their own part in things would mean facing their demons and faults which they are not prepared to do, so the minute things go wrong for them, they strike out and blame others.

They would rather maintain the grandiose delusion that they are one of the finest things in the world. They believe they are better than human.

TYPE 2, the damaged soul.

Because they have been very badly hurt at some point in their lives, maybe a trust as been betrayed, maybe somebody they depended on them left them, neglected them, or bullied them.

They subsequently feel afraid, deeply insecure and suspicious of all and not trusting of many.

They find it hard to believe there are good people in the world, and so when faced with good people, they try and hurt the good people, to confirm their belief that the good people don't actually exist.

Subsequently, the good people can't really help them, (as it's not their job to be punch-bags), so they leave, thus leaving the person as full as hate as they were to begin with.

That's the two main hateful types I feel I've come across anyway...

there are all sorts of people who live their life by hatred.

Maybe they have been treated with hatred their entire lives and feel like hatred is a way to enact revenge.

But there are some people (a lot of people in fact) who love being jerks. I think jerky bahavior and hatred is the very same thing. Terrorists just have more power that is all.

and there are also A LOT of so called 'socially acceptable people' who are filled with hatred, but the social controls they have learned even hide their motives behind their attitudes from themselves. The person who is the victim of their hatred however feels it, and can't do anything about it.

Hate is anger, fear and distrust. Some people have no idea that there is an alternative for them. They learned this negative way to respond; it's a dysfunctional way to protect the Self.

Also: they do not believe in hate's opposite, love, even when it is modeled for them.

I don't think anyone chooses this. Hatred is a product of fear. First you get scared, then you learn to hate. It becomes a vicious circle of hatred and abuse.

They feel like thats the only path they can take. It starts out with small things and then builds up until it totally consumes their life and before they know it it's the only thing they can do.