I'm going to just say I'm allergic to a certain ingredient instead of just asking for it to be taken off.
Why would you lie like that over something so petty?
I think they'll pay more attention that way.
I think there's nothing special about having an allergy.  Just say you don't like the ingredient, there's nothing wrong with that.  Remember, it's the restaurant's job to make you satisfied!
That does make sence.
You're the one paying them to make food for you. They need to do what you want.