A stranger walks into a bar and puts a pound coin on the counter and asks for half a pint of bitter. The barmaid asks him whether he would like Guinness or Worthington. The stranger asks for Guinness. Another complete stranger comes into the bar, puts a pound on the counter and also asks for half a pint of bitter. The barmaid immediately pulls half a pint of Guinness. How did she know what the second man, who was completely unknown to her, wanted?
(think in a crooked way for this one)
I haven't looked at the solution, and this may be out of left field, but say the 1st stranger was killed by the 2nd stranger after the 1st one left. Then the 2nd one put on the 1st stranger's clothes. When he walked into the bar, the barmaid recognizes the outfit and knows what the man wants.
Too farfetched?