A few hours ago my girlfriend and I went to Barnes and Noble. While browsing, I noticed the positions of the books.
Now, I can still remember the exact order of books I was interested in on which shelves.
I cannot for the life of me remember the route we took to get to the store, the faces of any other customers, how much the books cost whose prices I looked at, or how much the coffee I got cost.
We also went to a pet store (it's a quirk we share). I can recall each dog and cat I played with nearly perfectly. Which shelves had which types of cat toys and cat foods. But I have no idea where the store is, whether the person who owned the husky was a male or female, etc.
We then went to a gourmet grocery store. I can remember exactly how much per pound the Jamaican Blue Mountain is ($49.99), the prices of the other types of coffee, the location and brand of each coffee maker, and the exact kinds of curry sauces in which aisle. I do not remember its location, whether we talked to anyone, or details about the bakery supplies.
Yes, I can notice and remember those things which interest me, to a rather high degree. But I have little control over what I will find interesting, and no control over whether the details I archived would be at all useful to somebody else. This makes my memory a kind of crapshoot, in which I and anyone else will just have to hope I was in eidetic mode rather than passive mode.