Familiar sayings and where they came from ...
1."Fly by the seat of your pants": From early airplanes of 100 years ago. Think of the old string and canvas biplanes with almost no instruments or gauges. The pilot had to be alert and get the feedback from his own senses including the feeling of shifting weight due to the motion of the plane. To fly without charts or instruments, purely on what you could see, hear and feel was flying by the seat of your pants.
2."Bob's your uncle": A primarily British slang term. The rough translation is "It's easy as that". The etymology comes from 1887, when a British Prime Minister (first name Robert) appointed his nephew as minister for Ireland. The blatant nepotism eventually gave rise to the saying.
3. "Let's paint the town red": In Britain it was the drunken revelry of the gentry after a successful fox hunt. It's theorised by some that it is inspired by Dante's Inferno that mentions painting the world scarlet with sin. However, in United States slang "paint" can mean "drink". When someone's drunk their face and nose are flushed red, hence the analogy.
4."Three sheets to the wind?": Sailing reference. A sheet to the wind is a sail that has come loose. Three sheets means all your sails are loose and you are totally out of control.
