I'm still learning - I know this: the upshot is that every so often I get a project that allows/forces me to 'level-up' - I achieve something I previously only ever associated with other people and that's a great feeling and one of the reasons I keep going and probably the closest I get to doing "great" work. It's very rare that a whole project is great, anything complex has things I know are crap but are left in because the deadline is usually too close for comfort or the materials are horrendously expensive, but parts can be amazing. Little bits, jigs I make to cut tube in the right place etc - all elegant and brilliant, even if I do say so myself
Unfortunately, the feeling of doing good work is almost always, without fail, followed up by something like an email from the client saying that the "experts" think it should be different, or the info was wrong. It usually involves posting something brilliant through the table saw. My next project coming up is "fixing" probably one of the best models I've made so far - something I am genuinely proud of and can't imagine a few coats of bling-tastic blue and gold paint improving. (pix in 2010 sometime)
Unfortunately the clients are the ones paying for this shebang, so they get what they ask for. So it goes. They always seem to love it in the end.