How do you get to Carnegie Hall?
Practice.
Frono, kydog, I think that Steffan was just saying that you have to avoid the bad aspects of "practice" that turn a challenge into a chore. I struggle with this concept on a daily basis with my kids. Of course it's true that "just play" is not gonna' make a great player out of anybody.
I plateaued many, many years ago at essentially an intermediate level. Yeah, sure, I've learned new songs in the intervening decades, but I have no illusions that I will ever be a master of the guitar. I think it all depends on your own expectations for yourself. I was brought up in a very competitive music environment, and my trumpet has always remained the outlet for that -- but as an adult I've accepted my skill plateau there as well.
If I had chosen the professional route, I'm sure I'd have a different attitude, and many of you guys are far closer to that than I'll ever be.