Pet peeve du jour: using parsley as a garnish. If you serve me a meal with a sprig of parsley on top, I immediately move you from the mental category of “serious cook” to “making potato salad for the school barbeque”.
Seriously people, parsley is a herb. It should be used to add flavour to food, not as an afterthought touch of colour. If it doesn’t compliment the dish, I have to pick it off my food and leave it on the side of the plate like a sad, soggy little weed. Please, next time you find yourself reaching for the parsley because the dish looks “too beige”, just restrain yourself. I’ll thank you for it.