I'm pretty much the tortoise of the writing world. Pretty much every day, I drag myself a few steps forward, regardless of the circumstances. But I have to admit, my progress is sometimes speed-bumped by a bad review, a harsh (though usually well-deserved and ultimately helpful) critique, or less-than-encouraging news from the publishing front.
I expect better of myself, and sometimes I do manage an "I'll show you" attitude that gets me working harder and has seen me through a lot of tough times. But continuous, stoic indifference to negatives is a tough feat to pull off.
Fortunately, the opposite works, too. Whenever I'm given the slightest encouragement -- it could come from a reader, a critique partner, a reviewer, my agent, or an editor -- I harness its power to elevate my mood. Then I ride that burst of optimism as far as it will take me.
And sometimes, I save a kind e-mail or written comment in a folder, where I can take it out to warm my spirit on a bitterly-cold day.
As a result, I've become more likely to write other authors when I've loved something they've written, to share with my CPs how fortunate I feel to have such talent in my corner, and to offer encouragement to deserving up-and-comers. Because you never know when your words might be the very thing that bolster another's spirits and gets them through a rough patch into smoother waters.
One great thing about having writer friends is that everyone seems to instinctively understand that the best defense against rock-hard reality comes in the form of the camaraderie and encouragement we share.