Why you people so serious?

I know sometimes are the perfect time to be serious but not all the time! I am the youngest in the family,my brother turned 22 this year and now he won't play with me anymore he use to be so fun but now he's soooo serious and mean!! I try to be a bit funny or random and all i get is ''Stop being wierd!'' My family doesn't know how to have fun these days and it's NOT becuz of wrk!