When I'm bored in my room I act mentally handicapped
What's the benefit of acting mentally handicapped?
I just want to see if people notice my tricks
While you're in private and can do what you want, it is still inappropriate and ablist of you to accessorize people's struggles for your own entertainment. You need to rather educate yourself on how much they suffer and find something else to do for your boredom.
I'm just bad at being bored, though I realize this isn't sensitive of me
I'm glad you realize that it is insensitive behavior.  If you are bored, and enjoy performing, you could try harmless acting exercises that could be just as much fun.  Maybe try to see how long it takes others to notice that you are no longer using the letter "B".