Bostonguy, you'll have a blast.
Staples Center energy is among the lowest but probably the best when a game is close.
So if you're in a close game, you'll FEEL the crowd, probably the best crowd in the NBA in close games. It gets LOUD, especially when Ariza/Kobe/Farmar are on the floor.
If the Celtics are putting a beatdown on the Lakers, you might as well leave early and beat the traffic.
You can probably get away with wearing a Celtics jersey but I wouldn't advise it unless you like to take trash talking.