Old ones are the best

Went shopping with the wife on Saturday, and decided I needed to have a shit. Went to the toilets, found a cubicle and sat down. Suddenly, the guy next to me said, in a loud voice:

"Hi! How you doing?"

A bit confused, but ever polite, I replied, "Um, fine thanks.

"So, what are you up to?" he said.

"I'm, err, having a shit. You?"

Just as I was really getting worried, he says: "Sorry, mate, I'll have to call you back. Some cunt in the cubicle next door keeps talking to me."