It’s a very safe bet that everyone reading this has either directly had the following experience or knows someone who has—spouse, child, friend, relative or colleague:
You’re at home after work when your college friend calls you--her boyfriend just broke up with her. She didn’t see it coming. Everything was going fine, when out of nowhere, a letter showed up on her doormat; he’s had a change of heart and doesn’t think they should continue. She sobs; her voice shakes; you tell her you’re on your way.