Tournaments are a lot harder and take more of a toll on you. In a cash game you just sit and wait for a solid hand, or a time to bluff, and you're never in a hurry. In Tournaments you have the blinds catching up to your stack sometimes and you have to pick the right spots to steal blinds, pick the right spots to bluff, and hope you got your money in with the best of it... as well as a lot of pre-flop all-ins.
For instance... I played in a $100 freeroll freezout on CD Poker and had to bluff at so many pots after the second break... just to survive to make it into the money (which I barely did). And I know it's a freeroll, but the buy-in tourneys I've played in have been just as strenuous. BUT, I took that $1 to a .01/.02 NL ring game... and in the first hour I only played 3 hands, literally. On top of that I only won 2 of them, but my $1 turned into $4 (those hands I played AA,KK, and 99... 99 lost). So, as long as your patient, hands will eventually come to you in a cash game... in a tourney, sometimes you have to make your hands.