Humans are amazing machines but I think evolution QA team actually missed a few minor software bugs (as apposed to hardware bugs).
Here is what I've noticed so far
A single or a series of breathing diaphragm spasms, of variable spacing and duration.Most people have no control over hiccups. They eventually stop on their own, but why? ... does something reboot? (Alert blogger Greg P also noticed this too).
Involuntary muscle twitch which occurs during just as a person is beginning to fall asleepThis is a slightly more serious bug that most people have experienced. Just as we are about to enter sleep-mode, some neural signals are misinterpreted by the brain as "falling, oh no!" The resulting muscle twitch awakens the person. Stress and other conditions can cause an infinite loop of consciousness. More info on Hypnic jerk.
A phenomenon in which one feels a shiver running down the spine following urinationFormally known as Post-micturition convulsion syndrome, it confused me a lot growing up. It seemed to happen completely at random; I tried without success to replicate it, or predict when it would happen. It happens mostly in males. I didn't know it was a whole phenomenon until I Googled it this year.
Any more bugs you can think of?