Which is the best corny joke?

• Horse walks into a bar. Bartender says, "Why the long face?"

• Polar bear walks into a bar. Says to bartender: I'd like a gin (long pause) and tonic. Bartender says: What's with the big pause? Polar bear, holding up his paws, says: What? I'm a polar bear!

• Why is every marriage doomed to fail? Because the bride never marries the best man.

• Why is 6 afraid of 7? Because 7, 8, 9.

• Other: