I like the "burnout" = "slump" bit above. It's true. No one who's going out and slamming pigs (one might say he's being a slampig) all day gets burned out.
Personally, since I've been learning more and more about bass fishing (thanks to this site + experience), and been catching more and bigger fish than before, fishing has become much more satisfying and interesting. There's a real sense of satisfaction when you go out and piece together the puzzle of where the fish should be, how active they should be, what types of lures they're most likely to hit, and finally getting them to hit. Conversely, the bad days become more irritating because I think to myself, "Man, you spent all that time learning all this crap and you STILL can't catch a fish you loser!" >
But seriously, I don't know anyone who goes out for a full day (or even a couple hours) of fishing, gets skunked, then thinks, "Well, what a wonderful day that was!" Being out on the water itself is relaxing, but not if you're trying to catch fish and aren't catching any. Then it becomes annoying.
I agree with you to a certain extent jwo1124, we do need to keep it in the back of our minds that we fish to have fun, especially on those days when the bite is really tough and we're not really having that much fun. However, understand that "fun" is inextricably tied to catching fish, moreso for some than others. Even if you're lucky enough to be able to have fun when you're not catching fish, you'll have more fun if you do catch fish. I said above that it's not possible to be slamming pigs all day and not have fun, but if you somehow reach that point, it's time for a break.