18. The Slots on Truck Beds Are for Dividing Cargo with 2×4 Boards

If you’ve ever loaded a pickup truck, you’ve seen those rectangular slots or indentations along the inside walls but probably ignored them. They’re designed so you can slide standard 2×4 lumber boards across to create dividers that keep cargo from sliding around during transport.
It’s a simple, built-in organization feature most casual drivers never use or notice. Over-35s who’ve hauled furniture or tools for decades suddenly realize they’ve been fighting sliding loads the hard way all along.