edit: I should've been clear in stating that it is _unsolicited_ mail addressed to your name and address that is legally yours.
Is this in anyway based on any facts whatsoever or is this something you weer once told and are now repeating? A quick Google says it's up to 5 years jail for keeping misdelivered mail in the USA (depends on jurisdiction).
https://www.hg.org/legal-articles/theft-or-receipt-of-stolen...
Yes. https://about.usps.com/publications/pub300a/pub300a_v04_revi...
Incidentally, we've been having numerous postal issues at my complex because it doesn't have a full-time carrier assigned to the route. It's so bad, I had to get a PO Box.
My neighbors must be mostly thieves (keep) or too lazy (throw away) to bother correctly redelivering mis-delivered letters or packages most of the time. They are surprised like you're a fool for making an effort to redeliver them correctly. The complex is 98% white-collar, third-tier college graduates, single, between 24 and 35. I've had electronics, clothing, and random articles left in my box and at my door... these are mis-deliveries.
Misaddressed mail would be wrong name but correct address.
I however didn't go candy is the new toliet paper-hoarding Grinch over lazily mis-delivered snacks by doing the couriers' job for them. Maybe I shouldn't have because replacements, but neighbors and candy usually involves kids. Neighbors didn't even say "thanks," so I definitely should've kept them. No good deed ever gets you anywhere, kids; you must always appear to do something half benevolent and half selfish with an audience. Be Vito Corleone. Make them an offer they can't refuse. Since it was was couriered instead of postal mailed, postal laws don't apply and it reverts to property and commerce laws. Now if I conspired to give them half if they said they didn't receive it, that would've been conspiracy to commit fraud.