I doubt anyone could spend endless years at it, or an entire lifetime as many musician have, without having a good balance between wanting to improve and enjoying the music as it is.
Also, to be content with whatever level of dedication one has for it.
I talk to friends from time to time. After talking about their job, their mortgage, their fiance, snowboarding, playing soccer, etc... They say how they'd like to take up music, but are discouraged about being bad or not having good instruction. I think one can have the best advice from the best teacher, but it wouldn't mean anything unless they're able to put it into practice. So better to be honest, and if music is far down the priority list to accept it even if it means just crunching a few simple chords - one can still get a lot of enjoyment out of it.