I like the Norwegian penal system's view on prison terms: the punishment is the loss of liberty itself; there's no need to also treat prisoners inhumanely as an "additional" punishment -- which is what the U.S. generally does (and a lot of Americans agree with it). In the U.S. there seems to be this idea that "the worse you treat people in prison, the more it will scare people about going to prison". And yet, statistically that doesn't work. Norway's rate of recidivism is one of the lowest in the world, and nearly half that of the U.S. (Granted, this has a lot to do with social conditions outside of prison.)

If the goal of prison was "change behavior" rather than "make miserable", it might seem unfair ("bad people are getting away with it" etc.) but better for society in general (all of us). Yes, it won't work for everyone and there are some people who will never change and are just evil. But we tend to laser-focus on those few instead of the many who are not like that.