I've had packages arrive smashed, ripped open in shipping with contents missing. One time with somebody else's mail stuffed inside the box. Report it for investigation and then it just goes through an automated process that tells you "Nothing found" in 60 days. Report a post office known for stealing shit (going by Google reviews) to the postmaster general's office, and they just route the complaint back to that post office where the manager calls you for feedback.

Privatize the post office. Companies can screw up but at least then we'd have a choice.