Forgot to add...when I decided to pickup a guitar a year ago I did it because I just knew it would make me feel great...and it does! Its the only reason I play every day. It is quite a rush to hear myself even playing bits n pieces of classic rock tunes and just stumbling across chords that sound great.

Sometimes when I play some chord changes that sound great I can smash them out over and over and i never get bored!

Anyway your point about knowing why you are playing is really good advice and will just remember this if i get frustrated with a difficult part....just rock on to have fun and feel good :)