If you have multiple children, does show favoritism toward one affect that child or the other(s)?

It can cause the favored child to develop a sense of entitlement that will challenge other relationships. Or, the favored child may realize that the other child(ren) is treated differently and it could backfire on the parent. To notice that a parent favors 1 child wreaks havoc on the underdog! "If I'm not good enough for mom/dad, nobody will love me." Many people carried that way of thinking throughout their entire life!

It can like my mom favors my brother even tho I do everything for her. But I think I understand and it doesn't bother me. He is her only son and I don't care because I honestly don't like people.

Yes.

Playing favorites is never a good idea! My mother played favorites and so did my father. Well, the 2nd and 3rd child out of us four, ended up having a lot of problems because of it. Let's just say, they ended up being bad teens and having depression.

Obviously. Favoritism can be perceived as who is loved the most.

yes