When a bad memory you try to oppress comes rushing back suddenly, and you flinch with the horror of something stupid you did, as if you had been smacked.
slapping self in the face
"Aww, man, I just seeing you grill those hot dogs reminded me of something I try to forget-- that time in college I crashed that family reunion. The memory came back and totally Retrosmacked me."
One who falls in love with new people every year, or who falls in love again with their spouse/partner every year so their love seems like new
Seal and Heidi Klum seemed to be Reannusphilocaderians, with him coming up with elaborate celebrations of their love every anniversary they had together to keep their relationship like new.