The fact that they print jokes like these, secure in the knowledge that at least some of their readers will get all of the punchlines.

El Greco walks into a bar.
The bartender says, "Why the long face?"

Christo walks into a bar and starts draping everything in orange silk.
The bartender says, "Hey man, there's a ten dollar cover charge!"

Picasso walks into a bar.
The bartender says, "Why so blue?"

Henry Moore walks into a bar and asks for a drink.
The bartender says, "You need a drink like you need a hole in the head."

Thomas Eakins walks into a bar carrying an oar.
The bartender says, "Are you out of your skull?"

Toulouse Lautrec walks into a bar and asks for a drink. When he gets it he asks the bartender, "Can I pay you tomorrow? I'm a little short."