Am I mean just because I don't want to let cars go over when their lane runs out?
Why don't you want to let cars go over? They were in a hurry and trying to be considerate and letting them over won't make any difference to you.
No reason, I just don't want to let them go over.
You have no reason to not let cars into your lane, but this is not the way driving goes. You have to obey the law and let them in, otherwise there will be a bad accident and cause injury and possibly death.
I don't give a shit. I'm only doing it to enjoy the situation where I'm allowed to disobey traffic laws with no consequence.
There are going to be consequences if you don't follow the laws of the road. Just let them merge and everyone will get where they need to go.