The landlord in a local pub is an expert in judging the IQ of the punters. One day a new face enters the pub, the landlord talks with him for a short while and says: "Well, you must have an IQ well over 140." He introduces him to a man on the other end of the bar. They get to talk about Einstein's special and general theories of relativity as well as the philosophical links of Kant and Hegel and both enjoy a great night out in the pub.
An other new face is estimated nearer 90. He is brought to a corner of the pub where another bloke is watching a football match on tv. They get to talk the game, football in general and of course women and have a great night.
The third new face takes a bit more effort, which is understandable since the man only scores an IQ of 30. He gets taken along to a table in the back and planted on a chair next to a man who has been sitting there in silence for a while: "Right, trust my word for it, the two of you will get along just fine."
The two men slowly sip their pints for a very long time while looking at each other suspiciously. Until one says to the other: "So, which do you prefer, flatwounds or roundwounds?"