Why do so Many Authors Make their Characters Clumsy?

I woke up at 6:20 this morning with a terrible headache. I got up and played some Angry Birds, waiting to see if I was going to feel better, or go back to sleep, but neither thing happened.

Then I got up to go the bathroom, tripped over my own feet, knocked a pile of books to the floor, then hit my desk and knocked that around, fell over the cat and finally managed to go two steps.

I'll just try to stay away from bluffs and cliffs today...