"Passion is the genesis of genius."The surprising thing is, though, that you don't have to necessarily be passionate about your particular manuscript. You just need to have a strong feeling about something. Anything, really. Emotions are timeless and universal. They'll work in any genre and/or setting.
~ Tony Robbins
Words flow the fastest from my fingertips when I'm hyper-emotional, either negatively or positively. When strong feelings roil, the human psyche ignites, which usually results in a doggone fantastic word count for the day.
Now I'm not suggesting that if you're experiencing writer's block you go pick a fight to work up some passion. But it wouldn't hurt to whip out your laptop next time you're hyped. Even simply jotting down a few words about your feelings will be a kick-starter next time you get stuck.