I'm not going to allow my bf's younger brother to come hang out out with us for the 3 days he gets to visit me
Is the younger brother that annoying?
I don't like him. He is simple and stupid and I'm tired of hanging out with him
There are times you want to be around other people and not want other people to be there especially if they are a bit off-putting.
There is a difference between dislike and hate and I hate that person.
I understand you have strong feelings towards us other person. I think it would be beneficial to not harbor these negative feelings and to just focus on spending time with your significant other.