Do some people only imagine that they have an intolerance for certain foods?

Maybe they believe they have an intolerance, but then realize they’ve been eating things that contain whatever bad food in it all along, and nothing happens when they do.

An acquaintance had throat surgery today. A while ago she asked them for a shake and they said no, because she has egg allergies (supposedly) Well, she didn’t realize that ice cream has a LOT of egg in it and she’s been eating ice cream and shakes for years with no problem.

So, what does this mean?