It's wrong to read someone else's mail without their permission.
Larry's neighbor had been out of town for a couple of weeks.
Larry wanted to bring in the mail for his neighbor so it wouldn't pile up in the mailbox.
Larry picks up the neighbor's mail and passes each piece under their door.
Larry opens and reads each piece of mail before slipping it under the neighbor's door.
Larry's neighbor buys him a gift card for doing the favor for them.
The neighbor calls the police on Larry for mail tampering.