The package said in bold letters, "Mayonnaise!" or some such, and what I didn't realize until I got home was that it wasn't actually mayonnaise, but some sort of vegan/literally not mayonnaise alternative.
I wanted mayonnaise, I asked for mayonnaise, and I got something whole foods thought was healthier.
Now when I'm shopping at WF (rarely), I am extra vigilant about making sure that what I am seeing on the label is actually what I am getting in the container. In fact, I try to avoid "fancy" alternatives to normal foods, because I find that they often replace normal ingredients with things they think are better for me.
But I don't want that! I just want mayo, just give me mayo!
I've also had this where I buy sour cream, or cottage cheese, and get home to find out that it has, in tiny letters, "reduced fat sour cream!" - NO! I want the fat in that sour cream or cottage cheese, that's literally why I'm buying it!
edit: interestingly the mayo was actually called "just mayo", but that's newspeak. It literally is not mayo at all, it is a substitute for mayo that they think tastes similar. So "JUST MAYO" actually contains nothing that is mayo.