I always thought Human Nature was good. Not great, not bad. I like the message she's conveying and of course the video is pretty iconic, sexy and slick.
When I heard the MDNA tour studio version, which is essentially the original version with the inclusion of more full, layered backing vocals in the bridge and chorus.....? Wow! Those backing vocals take the song to the next level. I don't know why the backing vocals weren't on the original release.