The CEO's of Guinness, Miller and Corona are at a beer convention. After a day of meetings and speeches and schmoozing from vendors the three decide to meet up for dinner.
Once at the restaurant the waitress ask's them each what they would like to drink.
"I'll have a Miller" says the CEO of Miller.
"I'll have a Corona" says the CEO of Corona.
"I'll have a Coke" says the CEO of Guinness.
The other two CEO's stare at him and ask why he's not having a beer to which he says "Well if you two blokes aren't having a beer then neither am I".