I stopped explaining myself when I realized other people only understand from their level of perception... and we are all on our level of learning so don't blame someone because they're below or above you - we're all learning as best we can... ;-)
Are you nice? Mean people do upset me, though. Mostly people who take advantage of others and are inhumane. Inconsiderate and stuck up people (people who believe that they are superior to others) can be pretty annoying too.