I think I am mildly allergic to sweets (sugar? confectioners sugar?). I can't eat sweets, I get sick or almost sick. On Sunday I was told I had to try this cake frosting so I was polite (what is a fingerful of frosting going to do?) NOPE. Felt sick the rest of the day (ate some toast and had a glass of wine), woke up on Monday and barfed and felt sick most of Monday. Can sugar even do that? Maybe it's a mental thing? I can eat bread which has sugar and I am sure other things I eat have sugar but anything with frosting, super sugar bomb stuff makes me queasy, I don't even like fruit in my yogurt.  So tl;dr maybe some people decline shit because it makes them sick.