Cheers, Best, Peace. Lately, a lot of people are claiming that we end our emails wrong. I get it. As a journalist and writer/editor I've emailed with usage hounds for years, seen all the permutations. To date, "Warm best" remains the creepiest/funniest email closing that I've ever received (though it came from a kind teacher with stellar writing chops, so when I'd see it, I'd just laugh, call it Affectedly Endearing).
My take on today's valedictions may be a little contrarian. Despite the well-meaning advice offered in this piece that advocates for the death of email closings, I still use "Sincerely" sparingly, and more often, "All best" (rarely just "Best," which often seems cold). "Sincerely" isn't--or, rather, doesn't have to be--"fake." It's not when I use it, and come to think of it, anything that "warms" up "best" today in our icy Bot-times seems considerate.
That said, I'm also fine with never signing off, especially in short social or business communiques; sometimes that's the code two people follow. But it's nice to treat others the way you'd like to be treated. So if a colleague or friend goes to the trouble of signing off with a closing, I'll sign off with something. There's still a large population of people who'd consider it rude not to sign off, and I'd hate to hurt their feelings because I choose to live on Twitter.
Maybe I'm getting warmer as I approach my personal best (best = old, right?). Maybe I see where my professor was coming from. All I know is that I also happen to like it when someone who has sent a significant "letter" signs off with something sincere--whether it's "Sincerely," "Seeya," "Stop, Collaborate, and Listen," "Cease and Decist," or "Slades," a slangy combo of "see you" and "later" that my brilliant wife invented.
Hasn't this has gone on long enough?