There should be a word for that...

As if there wasn't enough words sitting stagnate in the English Dictionary that no one uses, like "gadabout" (meaning one who gads, esp. for curiosity or gossip), or "yokefellow" (meaning an intimate associate or partner), I'm going to go out on a limb and say that there's just not enough. Every now and then I'll come across a circumstance or set of events which you would think there would be some esoteric word for, but there's none to be found. Like whenever they play happy sounding music in a sad part of a movie to get some kind of ironic effect. Such is the case at the end of the old classic "Bridge on the River Kwai". Everyone's dying off, and there's this erie, happy tune being played in the background. Now you would think that in theatrical circles they would come up with some kind of word to describe this, that is, music being played which is at an opposite or contradictory mood as to what is happening in the scene in which it is played, but no, there is no such word (to the best of my knowledge). Or how about metaphors in which if you would reverse the saying of them would make no real sense at all. Like when someone says "so-and-so is a loose cannon", meaning that so-and-so is a very unpredictable person and such. If you were to say "so-and-so sure is a tight cannon" and you were trying to say that this person is a very stable person, it just wouldn't make sense to people. There should be a word to describe such restaints on metaphors. I had a couple other examples of things there should be words for, but they were so obscure I don't even remember them, haha... if I think of any more I'll update this entry.