Old, but still pretty accurate:

IN PRISON: You spend the majority of your time in a 10X10 cell.
AT WORK: You spend the majority of your time in an 8X8 cubicle.

IN PRISON: You get three meals a day.
AT WORK: You get a break for one meal and you have to pay for it.

IN PRISON: You get time off for good behaviour.
AT WORK: You get more work for good behaviour.

IN PRISON: The guard locks and unlocks all the doors for you.
AT WORK: You must often carry a security card and open all the doors for yourself.

IN PRISON: You can watch TV and play games.
AT WORK: You could get fired for watching TV and playing games.

IN PRISON: You get your own toilet.
AT WORK: You have to share the toilet with some people who pee on the seat.

IN PRISON: They allow your family and friends to visit.
AT WORK: You aren’t even supposed to speak to your family.

IN PRISON: All expenses are paid by the taxpayers with no work required.
AT WORK: You get to pay all your expenses to go to work, and they deduct taxes from your salary to pay for prisoners.

IN PRISON: You spend most of your life inside bars wanting to get out.
AT WORK: You spend most of your time wanting to get out and go inside bars.

IN PRISON: You must deal with sadistic wardens.
AT WORK: They are called managers.