It's very reasonable to think "Oh, crap, did I read this and not remember?" Because when you write, everything goes into the hopper, including memories of other stories and bits of them that stuck with you. How do you sort the "fanfic I read fairly recently" bits from "lifetime of reading and writing and having experiences" when you're in the zone? If there's a way, I don't know what it is.


Looked at from that angle, it's a wonder cries of plagiarism aren't more common.

I do sometimes see writers cry plagiarism when the other author used the same premise or general plot line (not the sort of step-by-step plotline I saw that made me go "Hm..."). They don't get that no one owns "boy wins girl, boy loses girl, boy gets girl back again."