Every day I discover new music that's interesting, imaginative, challenging, and deeply meaningful. I'm awed by how effortlessly such music flows and I'm impressed with the composer's technical mastery. That inspires me. It makes me want to create my own statements, writing music that matches that passion and vitality.
I also hear a lot of music that does not interest me, or engage my imagination, or seem to say much of anything at all. This inspires me, too! I can't help but ask myself what exactly I find lacking, what I would have done differently. Maybe the rhythms fall flat, or the harmonies are bland, or maybe it lacks emotional substance--and my mind immediately proposes alternatives and options.
Composition is a tricky thing. The difference between mundane and sublime can be as simple as a rest in just the right place, or a single unexpected accidental. There may be dozens of "good" solutions to a musical problem--or none. That's what keeps it interesting.