Emily Post had it right. Back in the '20s, she bestowed some solid advice to starry-eyed lovers that is still perfectly relevant today. If you can look past the dated sexist notions of what is appropriate for women versus men, the points she makes hold true.
In a section in the perennial book Etiquette, "The Letter No Woman Should Write," Post cautions that "often silly girls and foolish women write things that, when for instance that are read to a jury, sound quite different from what was innocently, but stupidly intended." Her warning, more than 80 years ago, that spilling one's guts in the heat of the moment is risky business is still just as relevant today, though a caution that applies to everyone, not just "silly girls and foolish women." Anyone is wont to be silly or foolish and be tempted to pour their heart out when the moment strikes. The "letter" that Post refers to could of course be modernized to mean an email, Tweet or Facebook post.
The takeaway? Get it out of your head, out of your heart, and sleep on it before you send it. As if Post prophesized the Internet's ability to make a message go viral, she warned, "Never write a letter to anyone -- no matter whom -- that would embarrass you were you to see it in a newspaper above your signature." Or, I'd add to that, a screen grab of your declaration on someone's Tumblr.
This all sounds terribly unromantic, doesn't it?
Wait for it.
Post encourages those seriously smitten to by all means put a pen to paper, but have some finesse. "If you are engaged, of course you should write love letters -- the most beautiful that you can -- but don't write baby-talk and other silliness that would make you feel idiotic were the letter to fall into cynical unromantic hands." More excellent advice. She even provides a sample:
...We all hope you'll be home in time for Carol's birthday. She has at last inveigled Mother into letting her have an all-black dress which we suspect was bought with the purpose of impressing you with her advanced age! Mother came in just as I wrote this and says to tell you she has a new receipt for chocolate cake that is even better than her old one. Laura will write very soon, she says, and we all send love.
Affectionately (or Ever devotedly),
Perhaps by modest 1920s' standards, this letter might have sent a young suitor's heart aflutter. If it doesn't induce swooning now, it is still undeniably a step up from a duck face selfie, "I miss you" text.