This has been culled from the RisusTalk list...
It seems like a lot of people don't understand that rule when it is used for serious play. I think it's because it was written for a comedy game in a comedic manner. But it can also be thought of in another way:
The Inappropriate Cliché rule is there to reward players for good roleplaying, for using what abilities they have in a way their opponent won't expect. It doesn't have to be something whacky (like Hairdresser in a serious fight). It is simply defined as any cliché the GM didn't specify was Appropriate for that combat.
In "Indiana Jones and the Last Crusade", Professors Jones (elder and younger) are being attacked by a German Fighter Pilot (3). Jones the younger has lost his pistol, so he is reduced to running away; he doesn't have an appropriate cliché, nor can he think of a clever use of one of his inappropriate clichés.
Jones the elder, however, can. He uses his Eccentric History Professor (4), remembers his Charlemagne, and stirs up the birds directly in the path of the airplane. In game terms, he rolls higher, so the birds smash into the plane. Inappropriate Cliché means the German pilot loses all three of his dice. Since to the victor go the spoils, Jones the elder's 'player' gets to decide the fate of the German, and he decides that he dies in a flaming crash.
Okay, this wasn't the most serious movie ever, but it also wasn't a comedy; I'd rate it as action/adventure. But it is illustrative of how a clever player can use inappropriate clichés even in a non-comedy environment.
I think that the three dice loss from an inappropriate cliché is a great way to reward players for being creative (and, as the rule notes, for roleplaying it really really really well).
All of the above is my opinion; your mileage may vary. But if this helps you, then I'm happy.