Those post-score routines (which occur during dead transition time) are fun for them and us.
TD celebrations can get out of hand. Chad Johnson used to take it to ridiculous extremes. Of course the NFL could diffuse the situation and actually get decent press by donating the fine to the Salvation Army. We all know the NFL will not do the right thing.
I have to agree with what Vince Lombardi had to say on the subject (often attributed to Barry Sanders);
When you get into the endzone, act like youve been there before.