Ouch

It's funny and yet totally reasonable how much pain affects us.  From a evolutionary and anatomical standpoint, pain is a necessary evil.  It allows our bodies to tell us when something isn't working quite right, and therefore allows us to adjust our behavior accordingly.
Some people are born with a genetic disorder which prevents pain receptors from functioning properly.  In other words, they feel no pain.  These poor children have to go through all sorts of terrible experiences.  Because they cannot feel pain, small children have been known to pull their own eyes out, because the texture of the eyeball and its location make it an interesting toy for those just mastering the use of their hands. 
But enough gruesome stories.  The point is that pain is very much necessary for an ordinary life.  But some pain just seems pointless.  A stitch in my side while running does nothing but slow me down and make me breathe harder, which only makes the pain worse.  What's the point?  Probably it's my body telling me to slow down and rest.  But in all honesty, if I were in pursuit of prey or running from a predator, such pain serves absolutely no purpose.
I am also amazed by the ability of people to sympathize with others' pain. When a friend looks exhausted and bedraggled, I can't help but feel a bit of that, too.  Happiness rubs off, too, but with not nearly as much of an effect.  All I can do is hug my friend tight and hope she recovers soon.

I'm grateful to warm (relatively, at least) weather that allows me to play Ultimate by night.