I hate going to a fancy restaurant and seeing chicken breast on the menu . . or grilled white fish. Because if I wanted to eat a fricking chicken breast with basic veggies, I could do that at home for about $4 and it would taste virtually identical to what they are serving. And the fish is always insanely expensive and, like the chicken breast, served in a really boring fashion. It pisses me off, because I imagine that if they didn't have those two dishes, they would probably have something awesome on there instead. The worst is when you go to some event where they only have two or three entree options - and one of them is always the chicken breast.
Other things that piss me off: insanely expensive caviar. I mean, caviar is good and all, but you just know that if it cost $5 a lb, barely anyone would eat it.
Scrambled egg sushi - and sushi with that brown bean cake thing on it. Especially when you see an otherwise awesome sushi combo platter, and there's that fvcking egg sushi in the corner, taking up all that room that could be used for a spicy tuna roll or something awesome.
Sandwiches at jewish delis - the ones that are just 3/4 lbs of deli meat piled 5 inches high on rye bread with nothing else. And the people who rave about how awesome they are. It's like eating a plate of pastrami with a fork and chasing it with a tiny slice of crappy bread. A decent sandwich needs a balance of at least 5 different ingredients.
Clam chowder at restaurants - especially clam chowder that anyone says is the best in town/world/etc. Because clams and clam juice are expensive, so restaurants have to cut it with extra milk, potatoes, flour and butter . . so no matter what you're getting at that restaurant, it's a diluted down fake version of proper clam chowder. Anything you make at home, with generous amounts of clams and juice, is almost guaranteed to be better than what a restaurant is making.
Spaghetti - I know it's identical to every other pasta except for its shape, but for some reason it almost always sucks. Can't hold sauce well, tricky to cook right.