This is Why
You just have to go and read this post on Becoming Ironman right now.
My favourite part:
Last weekend I got on my bike at 4:45am. Clear dawn was rising on the left side of my road, and the end of a sinister thunderstorm was looming on the right side of the road. Between them, inviting me to ride into it, was a rainbow. I thought, who else sees this now? People who choose to ride a bicycle at 4:45am, they’ve lost a bit of their minds. But it’s only when you lose your mind that you see some of the best the world is.
Suddenly it all makes sense.