It's Good Luck, Right?

I was sitting at the picnic yesterday when I felt a slap. I gave Shawn (who was sitting behind me) the benefit of the doubt, and assumed he was getting a bug off me rather than just randomly hitting me. But then I felt something run down my back. I told Shawn that the bug was now crawling down my back. He then informed me that there never was a bug, I had just gotten pooped on by a bird.