I detest my best friend's boyfriend.
What makes you detest your best friend's boyfriend?
He took her from me, and he is rude to me and he just not a nice person.
It is okay to be angry about being mistreated by your friend's boyfriend, however it is wrong to hate people. Find it in your heart to forgive him and have compassion for him.
No, I'm going to spend al lot of energy hating him, and trying to make his life horrible.
I don't think it's worth your time to hate your friend's boyfriend. I think you should try to forgive him, and if you can't then at least ignore him. Holding on to that hatred isn't healthy.