True. I’ve had two spectacular ones myself:

• I was printing some minis, and one of them came loose and knocked all the other ones loose as well. It took a long while before The noticed and the spaghetti buildup got to the point where the cooling fan for the hotend got tangled. The printer noticed and shut itself down, so no harm done.
• I don’t remember what happened, but the nozzle picked up a lot of snot that didn’t come off, and it only kept accumulating to the point where any extruded filament just kept adding to the booger. Luckily it was easy to remove as it was still pretty warm. And praise the gods for nozzle socks.