[Rek]

I think you will have a few different opinions on this one.

MTT and cashgames are like chalk and cheese in terms of strategy required. A very good grasp of mathmatics should ensure that a competent poker player becomes a winning one. I will never pass up a +EV in a cash game.

In touneys, there are so many different stages of play and whilst you want to play +EV in general there are times when I believe it is correct to pass on. For example early in a touney if crazy man is all in pre flop and I knew I had a slight +EV I am still folding. Whilst a double up is nice early on there is still no guarantee you will make the money. If you lose though you are dead. Good players will pass up small advantages early if it means their tourney life is on the line. No need to gamble if you feel you are a better player. No greater example of this than Phil "I can dodge bullets" Hellmuth. He will look for small pots early and lay any marginal advantage down if his life is at risk.

Later in touneys the strategy will change. Indeed there are times when getting all in as -EV is correct. You can't be blinded away.

So, you always would like to be +EV but in touneys the stage of the game is paramount. In cash games +EV means bring it on.