1. Suits + Tennis Shoes
I can't even count the number of times I've seen both men and women in suits and tennis shoes. It looks just plain wrong, and just plain sloppy. Are men's dress shoes (which are flat, mind you!) that uncomfortable? Even if they are, find more comfortable shoes, and please spare all of us the eyesore of the tennis shoes and suit "look."
Nothing screams more hippie than Birkenstock sandals. I don't care how comfortable they are, they don't work for anyone. If you must wear flip flops/sandals, how about Rainbow sandals? Those are so comfortable and much better looking than those buckled sandals.
3. Men's Fashion Week-Denim Tube Tops (what?!)
Fortunately, I didn't witness a man wearing this in public. However, it's Men's Fashion Week, and this is a definitely an instance of "what was the designer (specifically Jean Paul Gaultier) thinking?" A denim tube top is not chic for any man, even if it hails from Paris.