Dairy. I'm mildly allergic to it, but I love good cheese and good ice cream. I specify GOOD because low quality stuff just isn't worth the sinus junk I know I will have to put up with - don't talk to me about american cheese or store-brand ice cream. But some Blue Bell brand ice cream, or a good thick slice of that colby cheese we get from the Mennonite store... or some good havarti cheese, maybe on a slice of my homemade whole wheat sourdough bread... that is worth it. I will happily sniffle for the next few hours and deem it worth every sneeze to enjoy good ice cream or cheese.