Why did I do that?

I went out for a jog yesterday - you know how it is, so easy to fall off the exercise wagon and so hard to climb back on.  I've got a little route that I've set for myself along a little country lane and I keep occupied by marveling at the glories of the countryside (flowers along the side of the road, birds, deer that frolic in circles around my mailbox before gallivanting off across the fields) and paranoid about sunburn and ticks.  I am really afraid of sunburn and ticks. Because I am so afraid of ticks, I always run my fastest when I get to the short stretch of road with trees to one side, and I sort of obsessively pat at my back and shoulders, places I can't see where a tick might be hiding.

Anyhow, so I'm jogging along and I notice a spider on my shoulder.  I think it was a wolf spider, about the size of a dime.  Because I am such an old pro at country living, I immediately shrieked and swiped the thing off of me and then started hopping around in circles in a panic.

But then I was done with the panic and ready to move on.  And I should have.  But the spider was still there, sitting on the road.  Not moving, waiting for me to go away.  Innocent little spider, didn't hurt me at all.

And I stomped on it.  Out of spite, I guess?  I don't know.  But I've been thinking about it ever since.  Why did I kill that spider?  It was a horrible thing to do.  It was mean and senseless.  No, it's not a huge deal, but I regret it.