To the best of my recollection:
My most severe is that I'm anaphylactically, off-the-charts allergic to latex.
Other horrible and quite severe allergies I have:
tomato (and ANY tomato derivative), bananas, avocado, olive oil, macadamia nuts, walnuts, cashews and pecans, paprika, oregano, celery seed (far more concentrated and thereby more evil than just the stalk version), tamarind, cantaloupe, and coconut
Raw food allergies that disappear when the food gets cooked (something to do with a breakdown in the chemical makeup, or so I've been told):
cherries, nectarines, peaches, blueberries, carrots, apples, red grapes, celery (it is an evil, but only when raw)
I am severely lactose intolerant and have allergic asthma.
While this sounds awful, I'm one of the lucky ones. I can go to almost any restaurant and order something "plain" (i.e. a dry baked potato or crab legs steamed without the old bay seasoning). It may get me strange looks, rude behavior on behalf of whomever I'm speaking to about my order, or unwanted sympathy (don't "poor me" - I'm out and I'm eating and I'm conquering this as much as possible), but it's mine, and I own it.
~Your Allergic Diner