What is a good hobby/skill that most people should give a try, and why so?
What is something like a hobby or skill that you belive almost anybody should give a try, and what makes your suggestion so good compared to other things?
tying knots. All you need is a couple of pieces of string to get started. The right knot, well tied, is like a good friend - you can count on it. Shipyard workers sometimes make fun of how inexperienced mariners tie up their boats to a dock with "if you can't tie a knot, tie a lot!?" (full disclosure, I am a sailor).
someone else mentioned sign language - that is also extremely useful sometimes! My wife and I learned it when we learned to SCUBA. We do not have any deaf friends, but sometimes you meet a person who is reliant on sign, and if you can at least spell out some words, 'they are so grateful'.
I firmly believe that most active people should know how to tie a bowline knot one-handed. It's not hard relative to some other knots, and it could save a life.
You know I've often wanted to learn more knot tying options, especially when I'm doing things around the garden. I'll have to take your advice and learn some!
Do you have an recommendations of which ones to learn or resources?
Someone else here mentioned AnimatedKnots.com and I second that recommendation. For gardening, I'd learn the bowline and the trucker's hitch. The Trucker's Hitch is what I use to cinch a bundle of cut branches together with twine. You can get it really tight and it's really dead simple. You can also use it anywhere you want to stretch a line and have it not sag. I've used it to lash things to the roof of a car, too.