fear of death, the great motivator...
I went for a long (for me) ride today, about 50 miles. The last few (and first few) miles are along a pretty busy state highway, which I have to ride to go anywhere. On the way back, I had to stop about 2.5 miles from home for a train. I took a position in the middle of the lane, like I normally do at lights, stop signs and train crossings. Then I realized if i moved over after the tracks, I'd never get back into the straight lane at the light 0.75 miles ahead. So I ended sprinting from the tracks through the light. If you'd told me a half mile earlier that I'd have to do that, I'd have laughed at you and said no way. I had felt like I was going to die.