buypolar disorder 

A serious mental malady whereby you are convinced that you have sufficient persuasion/hyping-capabilities to sell ice to Eskimos.

Billy Mays is said to have been so skilled at salesmanship that he could sell ice to an Eskimo, but I never found him all that appealing or convincing, so maybe he just had buypolar disorder if he actually thought that about himself.

buypolar disorder by QuacksO May 8, 2019