Did you ever feel like you did something wrong but when you noticed your mistake,is too late to fix it?

so i was at my little brother's game but for some reason i feel like i should root for the opponent.I felt sympathy toward the opponent because they were short and for some reasons,i just dont want my brother's team to win.So the whole time, i cheered for the other team and i guess my brother's captain saw me and he seemed mad.should i be ashamed or sadden by my action?i