I'm about two weeks into one of my latest experiments... floor sitting. I got the idea from a book about the Blue Zones - four areas in the world that have an unusually high number of centenarians (100+ year olds). One of the people chronicled was a woman in Okinawa, Japan. She had no chairs in her house.
So I removed the legs from my desk and set it on top of stacked books about 12 inches off the floor to make it the right height for sitting cross-legged style. My son came home and asked what had happened. I said, "We got robbed". He asked why they hadn't taken the computer. "They wanted to improve my posture", I replied. He gave me a pained, teenager expression to intimate that he didn't appreciate my nerdy humor.
The first effect was obvious. I did a lot more ass-to-grass squatting. But as often happens when you try something new, there were secondary effects that I never could have guessed. Sitting on the floor, I found myself constantly shifting around and stretching. The current advice for dealing with an 8-hour desk job is to get up and stretch every 30 minutes, but that's hard for most people to put into practice. The other secondary effect is that I spend less time in front of the computer because it simply isn't that comfortable, so it forces me to be more intentional about that activity which translates into less time-wasting.