1. Your circumstances can change. And they do alot.
2. Genes is alot of nonsense. Lemme explain. When you look at chromosomes, they mainly only affect the physical reality of things. Hair color, eye color, weight (yes you could technically blame weight on genes, if you have a hormonal problem, though more likely it's lifestyle, which brings us to epigenetics; our choices affect our genes), bones, sex. You should not blame genes for our cirumstances, our personality, our attitude. These things are not inherited. You are bipolar because the overall mood at home was up and down. You are a jerk to others because nobody taught you how people feel. Stuff like that. To say those things are set in stone is to make a copout. But I've met a ton of people who like to make copouts. It's easier than #3.
3. Changing your attitude. Attitude indeed does make a difference. I'm speaking as someone who probably suffers from both schizoid and bipolar. Hooray for me. Offline, I am alot more shy, and my emotions in general are blunted. Amazingly, I was able to hold a job at the library for about two or three years. But usually, that's the limit except when working for myself. My mood typically interferes and is a bad match for employers. I know personally how attitude means the difference between a happy life where you get the girl (sorry lesbians, this notion that you are somehow jinxed romantically is mostly attitude, it's you doing it to yourself) and get to work on something valuable to you, and being stuck in a dead-end job or being unemployed or lonely.
That said, I'm oddly happier when things aren't good or bad. Too much happening is draining even if things seem good. And since I am wary of happiness, I seem to screw it up. I just don't like being alobe. But I can't get along with most people. So in the end, closing off my emotions, and hoping nobody bothers me is what I want I guess. But they always do.
Watch. By the end of today, even though this answer is perfectly fine, I will likely receive two downvotes, if not three. Some people on this forum apparently hate everything I say.