I haven't yet seen season 3 or 4 but from the first seasons, I considered Joffrey to be one of the characters the show dealt with the best. He's still an absolutely terrible person but by the TV show was able to present moments where you could really understand how he came to be that way, since he was a psychopath who was spoiled rotten by his mother and doesn't seem to have had much relationship at all with the man he believed was his father.

And yeah, Jack Gleeson is amazing.