1) I've received a bunch of Fw: emails from an Australian person over the years that I ignored as spam. Until he sent a very personal one, inviting me to catch up over beers since it's been so long, at which point I took pity and replied along the lines of "Hello! This is not the address of who you think it is. You're emailing the wrong person. Have a nice day." To which he replied "Lol, nice one!" Eventually the emails stopped.
2) I received a message from a major American company that if I didn't take action urgently, something or other would happen to my requested service. Ok, fine. Then within the next 5 months I've received at least half a dozen emails from them titled "FINAL WARNING: ...", stressing just how important it was for me to acknowledge it. I suspect the company is run by the people behind the Final Destination films or the Final Fantasy games.