Colin Cowherd made a good comment the other day on his radio show. He said it wasn't only disrespectful to your opponents, but to your teammates as well. By celebrating you are upstaging your teammates that helped you get to the endzone and you're like "Wait, wait let me dance, then you can congratulate me even though you were the one who threw me the TD/threw me the block that let me get here." I think it's selfish.