We have some cute oil lamps shaped like dragons (when lit, flames come out of their nostrils). They take ages to light. So, many moons ago, I bought a gas lighter to reduce the number of matches one goes through. Time passed. After a considerable interval of inactivity, I bought a cylinder of gas to fill said lighter. And yesterday, months later, I got around to taking the lighter out of the package, and attempted to fill it.
Turns out that the cylinder's nozzle is too big to connect to the lighter's input, and so goes everywhere except into the lighter. Bah.
(and, just to add insult to injury, the lighter contains absolutely no instructions on how to light it, even if there was some gas in it. Took me ages to find the hidden mechanism...)