screw "them".. you don't need 'em.

Yes, it is good that you work on the parts that bother you. And you may need to at least pretend to be a nice person in professional life. But in your personal life? hell, I know enough people who would like a character like yours. You just need to meet the right people. They are probably like you, but your anger/not-nice-est goes in the same direction, so you might stick together. There might be other people like you that are contradictory to you, so you will get in a fight with them (just try to ignore them and never meet them again)..

And people talk behind your back: I got news for you.. that happens to literally everybody. You are just in a luxury position to know when, why and what they talk about you.. you might aswell use it in your advantage.

I don't know you personally, but it is never too late to change the things you don't like.. and there are always people to find that can become great friends (or maybe more).. you just may have to look in other corners of the world than you are used to.