Obscure movie reference time... the movie's not so obscure, but people may see the relationship as being a little convoluded

There's a very nicely done scene in Adaption. where Chris Cooper's Character Laroche goes on and on about he spent some portion of his life obsessed with fish. He studied them incessantly and it consumed every aspect of his being. His universe revolved around learning more and more about fish. And then one day...

John Laroche: Then one morning, I woke up and said, "F$@# fish." I renounce fish, I will never set foot in that ocean again. And there hasn't been a time where I have stuck so much as a toe back in that ocean.
Susan Orlean: But why?
John Laroche: Done with fish.

There could be any number of reasons a person quits cycling. Not getting any better, so they quit.. Burnt out.. Found something better... Then there's the possibility that there is no 'reason'; they just quit.