Rowuk, I have to kind of disagree with you, but I think this is more a matter of differing perspective and emphasis than anything else. I'd like to explain myself more fully and maybe you can tell me what you think. I've read a lot of your posts and have come to respect your opinions, so I'd love to discuss this matter more fully.
I do get a great feeling when I get my paycheck as a reward for the hours I've put in and I love making people happy, but I could have made a lot more money with much better work hours as an engineer and I could make a lot more people happy playing piano at nursing homes! What I'm getting at is that I believe there is a deeper purpose that is fulfilled when we play. When you make music for any reason, you are giving voice to your soul and therefore making something more real and more genuine than many people ever experience. Mahler said "If a composer could say what he had to say in words he would not bother trying to say it in music." I think the same could be said for the performer. Just about any of us could make better money another way, but would never be truly happy because we need that outlet, that form of expression.
I enjoy turning up the metronome as much as anybody else, but I also enjoy getting my mile run time down and I wouldn't want to be a professional runner for anything! I think there's something about music that keeps us coming back for more punishment and that drives us to excel.
So in a sense, "the right reason is one that works," whether it is not sucking or watching great players or the next number on the metronome, but I believe that the motive behind all the reasons (or the "base" reason if you will) is not pragmatic, but that of expression. That's why we chose music and that's why we keep at it diligently.