Two dolts were out hunting and got lost in the woods. As they wandered they came upon the tracks.

Clem: Look! Deer tracks!
Slim: No they're not. They're bear tracks.
Clem: No stupid, they're deer tracks.
Slim: You can't fool me, you know those are bear tracks.

They argued and argued on the tracks. We'll never know who's right because the train just ran over them.