Even if we didn't have the science to back it up, we
instinctively know that sitting all day is bad for your posture
and back. We've already covered how stretching your wrists can
prevent pain there, but reddit user thefalcone found this simple
back stretch that can alleviate pain and tightness.  It's called
the piriformis stretch, with the piriformis being the muscle
around your spine, ass and pelvis area. (I'm not a doctor.) It's
quite easy to do, and just requires you to cross your legs as
shown above, keeping your back straight and leaning forward a
bit. This is ultra important if you sit in a lousy office chair
all day, and just takes a few minutes every hour or two to
maintain your health.  Alternatively, you can approach your boss
and say that if he wants to gain about 30 minutes of
productivity time every single day, he should buy you a nice
Herman Miller or Steelcase chair. That will easily pay off after
a year or two.  YouTube | via Reddit