This theme keeps coming up again and again with Federer - the love of playing the game as his primary motivating factor. Andrew Castle said yesterday in commentary:
It's about the joy of hitting the ball. That's why he came back.'
Great reminder that fundamentally tennis is a game. There to be 'played' and enjoyed. The powerful intrinsic motivation that comes from striving to master it in all its rich dimensions.
If you don't love it it's unlikely you'll stick at it, no matter what external rewards (riches, rankings, kudos/status etc) are to be gained.
Thanks Fed and Rafa for something truly amazing yesterday.