Mystery (one [postal])

Three-wheeled Mail Collection Motorcycle; Unidentified photographer; c. 1912: USA
National Postal Museum; U.S. Mail Trucks; Image ID: A.2006-74

One day, a couple years ago, I mailed a letter. Not an important letter, just a note to my sister about something or other with possibly a mail clipping. We occasionally still do that, internet/email bedamned. So, I was in a hurry when I sent this letter, signing it quickly in the return address area "lel." Just "lel." Nothing else. I dropped it in the blue mailbox on the corner near my house, and went on my merry, hurried way to work.

Jump forward a month. I open my mailbox in the foyer of my apartment building. Junk mail, weeklys, junk mail, credit card.... what's this? Oh, the letter to my sister. Crap, I'm an idiot and forgot to put a stamp on it. Pfffft. I wandered up the three flights of stairs to my apartment, mentally sorting recycling, and formulating a plan to give the letter to my sister that weekend when I saw her... when it struck me.

I looked at the letter again. Sure, no stamp, but also? No Return Address. No Return Address!!! The letter said "lel." Not my full name, or even just my last name. LEL! K. Thinking. Hm. Maybe they traced to my....no. I dropped in it the general blue mailbox on the corner outside the dry cleaners. How did it end up back in my mailbox? How did they know? Um. Huh.

I have never figured this out. To this day, baffled. I give my mystery to you. If anyone has any idea how this amazing feat of postalness happened, I would love to know. Otherwise, I will just conclude the postal service employs wizards.