Can anyone explain in laymans terms why your gear sound better after warm up

I get burn in... should be called burn off just to get the manufacturing process off all the different manufacturers and parts to sweat off the packaging and sealants. But a light bulb is on or off. So SS gear in theory should sound the same. A light bulb does not get brighter after an hour. Is it your ears get programmed? Or is there and actual technical reason that it sounds better? Please pretend Im a four year old cause with Electronics I am.

-ALLGOOD