I don't think I agree with ClvDad and Jemaz for once. We don't know the "whole story" and where do you draw that celebration line. Maybe baseball HR's celebrations will turn into the touchdown or dunk equivilents. Before you know it a player will be on top of the dugout after a homer doing a little "bump-n-grind". It is a snowball effect.
That would make me puke. Sorry for the "old school" but give me a curtain call with a tip of the hat anyday.
The devils advocate might suggest that maybe Lastings was asked by management beforehand to maintain his cool, or, past history of his excitable personality resulted in sub-par play later in a game and management wanted to nip it in the bud right off the bat.
Who knows. But I think historically a rookies celebrations are usually berated by someone. As a fan we might think it's excitable, as an older teammate or manager I might see it in a different light.