Someone registered for Facebook with myname@gmail.com. I'd registered with my.name@gmail.com and when I got the email that I'd added the account I clicked yes before reading (that's a mistake you make at most once) and now that guy has a Facebook account I can't log in to and I can't remove this email from the account and I can't remove the notifications either.

Part of the reason is that Facebook verifies you're the owner of the email if you say "someone else has my email" by sending you an email which you have to reply to. But Google will reply to all of them with the canonical sign-up so mine has my.name@gmail.com that the reply goes out with, which doesn't match so I'm stuck marking all Facebook notifications as spam.