Look. DON'T try to act like Clint Eastwood etc, I SEVERELY ****ed myself up by being too serious because I was trying to be "alpha", I made myself turn my head slow and everything.
Just please don't, it really really ****ed me up doing that, it was VERY hard to get out of the hole I dug for myself by forcing myself to stop laughing and telling jokes etc until that became my personality. Honestly you don't want to do that. Yeah it's hard to sum up in just this post, but I assure you it seriously affected my life for a few years to the point where it was hard to connect with others because I could no longer lighten up and have fun and constantly had to seem "cool and collected" etc, I programmed myself that way.
FORGET the alpha thing and just be normal, honestly. If you want to be "alpha" just learn how to be able to give things back to people twice as bad as they give you. If they make a slightly biting remark about you, say something really witty back and pwn them so everyone laughs at him. You'll establish your place at the top of the deck pretty quickly.
