This is an interesting thread. I think the biggest lesson you can learn from the responses here is that there are many reasons people enjoy FF. Some of them are in direct disagreement with other folks' reasons.
Some people say playing in more leagues is the key. That works great for them, and whatever works is what's best. For me, the trick was to cut back to only one league. The fact that I was winning in some leagues and not in others made it just kind of a wash for me. To me it also sucked that a player would do great for me in one league, but the same guy might beat me in another league. Kinda took the juice out of it for me. I can deal with losing, though I haven't in a long time. I just chalk it up to experience and try to learn something from it. I'd rather feel the winning and the losing than feel nothing because I'm in 5 leagues and everything cancels out.
Another of the previous poster's ideas that rang true with me was that I found it more enjoyable to focus less on my ff team's scoring on Sunday, and more on the game of football. You know...the reasons you watch football in the first place...the great throws, runs, catches, hits, rivalries, coaching moves and blunders, etc...and if there's a dud of a game coming on, just blow it off and do something with your family or friends. Chances are nobody else in your house likes this stuff...at...all. Keep that in mind.
A minor point...Something else that's fun is to occasionally draft or pickup a player from a team you like or that you're a fan of who you also think has ff potential. It makes it that much more fun to watch them on Sunday.
People like ff for different reasons. Maybe none of that works for you. The main thing you have to do is find what you like about the hobby and emphasize that. Then de-emphasize the negative aspects.
Have fun.