Eavesdropping
Overheard at the shelter...

Man 1: ...I don't know, it seemed like a good idea at the time.
Man 2: Well you know what they say. Hindsight is 50/50.
Man 1 (laughing): It's 20/20.
Man 2: What's 20/20?
Man 1: Hindsight. You know, like vision. 20/20 vision.
Man 2: That's stupid. 20 and 20 is only 40. It's 50/50. If you have 50/50 eyesight then your eyes are 100% perfect.