Bowline

The bowline makes a fixed loop that won't slip, and unties easily even after it's been loaded hard. If you learn one knot, learn this one.

When to use it

rescue     a loop around a person, not a noose
anchor     tie off a tarp or a boat line
lifeline    secure yourself to a line that holds

The trick

The rabbit comes out of the hole, around the tree, and back down the hole. Say it once and your hands will remember it forever.