Not to be a picky pedant, but why do people sign emails with “Best?”

Do they mean best regards? Best wishes? Best in show?

Best what?

I know that best means well. They could sign the email Worst, which wouldn’t be good at all. Best is definitely better than worst.

But “best” all by itself seems incomplete to me, like the signer forgot the rest. And I’m seeing it more these days, especially in email business correspondence.
Anyone know?

Best regards,

GT