Basic Sit 'n Go Questions Answered Here

[suitsme]

I have a more general question about SnG's. I normally play cash games but this question came to me when I played a live SnG with some friends (lets say equally good-bad players).

We're in the first blind -level and everybody has aproximately 100BBs. To make a long story short the SB does a slightly +EV push on the flop for lets say 90BB.
Gets called, looses the hand and is out of the game.

My question: Is a +EV action in a SnG always a good move? Which other things should we take in consideration also?