I find it erally interesting that some people really think anger is inevitable. I don't get angry either. And it's not that I do but react differently to it or choose not to display it. Really I just don't get angry. I accept things as they are - calmly - and choose to respond.
However, I will sometimes display anger as a way to communicate with others. Some people might call this manipulative - but sometimes if you don't respond to something does with a bit of emotion they don't give credit to the serious nature of the consequences of their actions. So sometimes I will show anger when it's appropriate - but it's an act.
To get to a point where this is the default mindset, you have to be very calm. Meditation helps.
BTW I just ran across your site and I like it a lot. I really like your outlook on things.