You’ve probably heard it before: righty tighty, lefty loosey. It sounds like something a grandparent made up, but it’s genuinely one of the most useful things to just have memorized. Turn a screw or bolt to the right (clockwise) to tighten it. Turn it to the left (counterclockwise) to loosen it. That’s it.
This works on almost every threaded thing you’ll ever touch — screws, bolts, nuts, jar lids, light bulbs, hose connections. The clockwise-to-tighten standard is so universal that most people go their whole lives without ever thinking about it.
Why clockwise? One widely cited reason is how the human arm naturally moves. For a right-handed person, the motion used to apply force with a screwdriver — called supination — tends to rotate the wrist clockwise, and since most of the world is right-handed, the design standard built around that motion stuck.
Now, the exception. Left-hand threads do exist, and they work the opposite way — counterclockwise tightens, clockwise loosens. They show up in specific situations where spinning machinery could cause a normal right-hand thread to gradually unscrew itself. Think bicycle pedals (the left one is standardly reverse-threaded), certain power tools, and some engine parts. If something keeps loosening no matter how much you tighten it, there’s a decent chance it’s left-handed.
But in everyday life? Righty tighty. It’ll get you through almost everything.