I hate when the English language integrates phrases from other languages into the vernacular. Examples:
I hate when people describe a movie as a "tour de force." Those people should be shot.
People who describe a novel as a "bildungsroman" should be publicly flayed.
People who have a "laissez-faire" attitude toward things, or are "blase" about anything, should be slowly killed using only a cheese grater.
And finally, anyone who describes any art as having a "jes ne sais quoi" quality about it should have his/her "joi de vivre" mercilessly beaten out of him/her.