Aesop's Fables 18

 
The Bald Man and the Fly

There was once a Bald Man who sat down after work on a hot summer's day. A Fly came up and kept buzzing about his bald pate, and stinging him from time to time. 

The Man aimed a blow at his little enemy, but—whack—his palm came on his head instead; again the Fly tormented him, but this time the Man was wiser and said: 

"You will only injure yourself if you take notice of despicable enemies."