I know I am going to sound like a pedant but there are too many people with poor posture while taking photos.
I see this all the time while attending photowalks. People tend to shoot like overgrown bats with elbows away from their bodies. Bad posture results in too many OOF shots that people can possibly imagine.
My system is simple, elbows tucked in, balance body against anything that is available (if possible) and don't breathe while taking a shot.
I'll give you a +1 on that, I love the people that zoom in or out by leaning rather than take a step. Sometimes they lean so far that you can see the muscle tremors from the strain as wall as the bad posture sway. Must be a miracle if they get in focus pics.
Actually, slowly and smoothly exhaling while firing the shutter gets less motion than holding the breath. 2 second handheld shots on my Hasselblad doing this!
Not when you have tucked in your elbows into your beer belly... No sir.
That reminds me, I need to get back in shape.