For better or for worse, what anime was the best adaptation of its source material?

i know that people often complain that a show "wasn't faithful enough" or strayed too far with fillers or just plain divergent stories. (honestly, I don't care as long as the show itself is good lol.)But what about the opposite? What shows did exceedingly well at adapting thier source, even if the source was shit(or gold) to begin with?...EDIT: what I really meant to ask was "what was the most faithful adaptation, but I derped. Oh well, what was the best, anyways? http://ift.tt/1Nac1JE