This is going to sound stupid, but lately I've been getting my motivation from my 9 month old.
The boy is constantly falling, slipping, wiping out and does that stop him? Nope, he just gets up and goes at it again and he may have even learned how to fall a little more softly in the process. Another thing he does is he sees something across the room, puts his head down (he's still crawling) and books it across the room in record time. It always makes me a little nervous because he's not really looking ahead (he's just barreling down on that object of desire.) But most of the time he gets there without smacking into any walls and if he does he just kinda looks around, reassess the situation, finds the object again and barrels down on it until he gets there.
So if a 9 month old never gets too frustrated to quit, why the hell would I?