Guild Wars 2

This hint is simply can’t be scored. I’ve told my friends to spam me with letter. I had 10 letters, started to delete em and got like 6-7 more. And still hint isn’t achieved.
82\83 hints in achievment interface is irritating.

This is a tricky one. You actually need to have 10 unread mail, so while you get your friends to spam you, let your mailbox fill up to 10 before opening it.

Oh, thanks, I’d never guess

Also, it helps to delete all extraneous mails (hearts, personal story, dungeon, free gifts from Anet, gem store purchases, living story, etc); only emails from real people count.