Why are notable prisoners sometimes comfortably housed?

I know of a US citizen who committed pretty brutal crimes in Afghanistan pre-Taliban, and went to a notorious Afghan prison. He had a dorm-like cell and was reportedly given alcohol and movies. The US had no known connection to this guy, and his crimes were abnormal and severe enough that in my opinion it'd be hard to classify them as justifiable in any way.

I've heard tales of ex-dictator(s), mobsters, and similarly influential people being given caviar and alcohol, and I suppose nice private cells, as well.

Why does this happen?

Edit to provide another specific example (one I had in mind while writing the question): Slobodan Milošević is said to have had extravagant food and alcohol while imprisoned.