Back in the late 70s I bought a portable (as long as you had been working out) B&W TV that was basically an oblong box with a handle on top, a 14" square Perspex screen and two dials on the front right hand side. Sold it at a car boot sale in the early 90s. About half an hour later the bloke brought it back and said "This is not a microwave" and wanted his fiver back. I gave it him but with the comment "What did you think the aerial was for?"