In a somewhat reversed version of the previous GBAChef this time it is foods that you dislike but people in general would call a staple of their diet but for the fact they are usually not great for you or are quite expensive.
Popular examples include
Bacon
This is the internet so I assume this does not need backing up. Still http://xkcd.com/418/
Coffee
Tea
I am told that as I have some blood of an Englishman
Some people do not eat dairy which I find a bit odd but there are good reasons for some of it.
Salt
Unless the recipe chemically demands it I will tend to avoid it.
UK wise it has to be mushy peas.
A chip shop staple and horrible slimy stuff as far as I am concerned.
I do not like tomatoes and tomatoes do not like me so that does also mean I miss out in pizza unless I want to kill every vampire in a 3 block radius by eating a garlic pizza or waste my precious jarred peppers on something as boring as pizza. However it is quite hard to avoid them as they are a really cheap bulking agent used almost everywhere.
I have hard time trusting people that do not like white chocolate.