Aragorn and Arwen: what happens when you forget the Westermarck effect

Clearly if Elrond cared so much about his daughter not marrying a mortal he ought to have made sure that she spent at least a year being annoyed by each successive heir of the Dúnedain toddling round going "But why, Lady Arwen?"

OTOH, perhaps Elrond did remember, and that's why Arwen wasn't around: she'd had it up to here with the whole thing, and this time as soon as Gilraen turned up, Arwen packed her bags for Lórien. Which unfortunately meant that she arrived back in Rivendell just in time to think he was rather sweet, if not particularly interesting to her personally, as a handsome twenty year old who was feeling pretty good about himself after performing great deeds in company with his (many times removed) cousins, and then think "cor, he turned out all right" when they met another thirty years later. Which to my mind Galadriel definitely arranged.

Yes, I am slowly making my way through the Appendices.