What harmless prejudices do you indulge?

I’m using “prejudice” in the second sense, as defined here: that is, an opinion formed in advance of or without knowledge or information.

For example, when I was a kid I thought nobody would give a horrid-sounding name like “mushroom” to something that was any good, so I refused to even taste mushrooms and declared that I hated them. That was silly but, all in all, harmless (and I outgrew it).

I’m not here to entertain arguments about why no prejudices are harmless or argue about the meaning of the word. I’m asking where in your life you go ahead and let irrational biases influence your thoughts or actions.

In my case, for example, if the sight of an author’s name irritates me, I won’t read any of the person’s books. It’s not as if there weren’t plenty of other things to read, and at my age I don’t need anyone telling me what I can’t miss. I don’t claim that the books have no value—only that I don’t want to read them. It’s a perfectly harmless private indulgence, and one that I have never even tried to explain or justify to anyone.