Which is true about almost everything in life. The more you smile, the more you find something to smile about (and nip those wrinkles in the bud while you're at it). The more you moan and groan, the more disgruntled you become. The more you discover, the more you realise how much is out there still waiting to be discovered.
And when you average 500 words a day, it takes blood and sweat to push that up to 2000 words. But suddenly, it's just as hard to write less.
Yeah, I'm feeling slightly philosophical today :)