It's a costume-related list, so it only took moments for Godwin's law to kick in and "authenticity nazis" and "costume nazis" to come up, and (not surprisingly) offend a bunch of folks because of the Nazi reference.
Mind you, I'm a big fan of Donna Barr's humorous and satirical Desert Peach stories. I'm totally with Mel Brooks in that ridicule is the best offense against real fascists and folks that think fascism is cool; they just can't take it. Even Hogan's Heroes with its hokey sit-com formula (pretty inappropriate in relation to the real horror of the Third Reich) has some merit in making laughing-stocks of the Nazis.
Back to the offensensitivity, though. You don't diminish the power of an image and a movement by restricting its name to hushed discussions that practically revere its horror. You also don't make any point well by engaging in hyperbole that equates emo personal drama with the worst horror of the 20th century.
The funny thing is, in the greater context, I do have a few historical costume pet peeves.
I hate bad footwear. Yeah, I wore bad footwear for quite a while, but I got over it. Tennish shoes? Trainers? Gack. Shoes are hard to make, but it's possible to get decent shoes without paying too much. They don't even have to be the right shoes, they just have to be something that doesn't stick out like a sore toe. Dreamshoes and faire boots may not be "right" but they blend better into the illusion. Modern zori (men's zori, at least) and geta may not be period, but they don't destroy the illusion (women's modern zori are a bit precious and over the top).
I hate missing headgear. Hats are an essential piece of clothing for many periods and cultures. Part of it comes from working faire. When I started, I could almost always identify other performers even if I didn't know them; they were the ones wearing hats. Nobody else bothered. Faire patrons who come in costume seem to have noticed this, and it's now common to see costumed patrons who have hats. The modern aversion to hats destroys the illusion for me.
Mind you, I'm not going to go running up to someone saying "these shoes suck."