I play tournaments because then the idiots who play Q-8 off are knocked out early and you don't have to deal with them sucking out on you.
Just winning money isn't much of a thrill for me. The middle stages of a tournament are the best for strategic play so I enjoy that.
The middle stages of a tournament have a lot of interesting decisions as to when to steal blinds, etc. but as tournaments force the game into increasingly smaller-stack decisions, they lack the psychological depth of a deep stack cash game.
As Ivey says, many of the "big tournament stars" these days would not be able to walk into a professional level cash game and make any money. Now don't get me wrong; I'm not saying that tournaments don't require skill--they definitely do, it's just a different
kind of skill because stacks are so much shorter and the variance is HUGE.
Tournaments are essentially maximizing fold equity and building your stack so that you, by virtue of a larger stack, are more likely to win the inevitable battle of coin flips that ends the tournament as stacks get smaller relative to the blinds and the game degrades further and further into an all in or fold battle. In this sense, you could say that tournaments are about "talking other players down"--you don't want to get into a big confrontation very often because if you lose, you're done, even if you got your money in on a +EV situation.
Cash games, on the other hand, are more about actually learning to win when you have to go to war. The level of play intricacy possible with stacks of 100 blinds, 200 blinds, or even more just dwarfs the relatively simple "do I shove or fold?" tournament decisions. You have to go out there and actively create your own edge--no blind raise is ever going to force your opponents to put money in bad.
The larger your stack, the more options you have for how to play various hands. Implied odds become so vitally important in deep stack poker that preflop hand standards are much more relaxed and that opens the door for all kinds of different creative plays. There isn't much room for getting creative when the blind is 500 and you're sitting on a 3000 stack. Your only decision each round is to shove or fold and hope for the best--that's not all that interesting to me, even if there is a fair amount of strategy in deciding when the best time to shove is.
And I'll play against Q8 all day long, with a wide variety of hands, if I have position. If my cash opponents are playing bad hands in bad position, I'd rather encourage them to keep doing so--more money for me!