I'm going to call out my friend's roomate for constantly interrupting me
Are you going to try to talk to him?
I'd like to, but I think he first has something to say about me
It's understandable that you are frustrated with being interruped. You should ask your friend if this is a habit that his roommate has, that way you know that you should not take offense to being interrupted.
He is not a nice person and quite stupid too. I just feel so angry inside.
I am sorry that you are feeling that way. You must be really frustrated that this person keeps on interrupting you.