It seems that the 'ends justify the means' is almost the OPPOSITE of what the Jedi do.

Luke getting pissed and killing Vader and then Palpy would have served to protect the people he loved, but it was exactly what he WASN'T supposed to do.

Anakin justified all his attrocities because he wanted to save the person he loved. He was the bad guy.

I think Qui-Gonn was kind of a freewheeling Jedi hippy, maybe even a bit of an embarassment to the Order. He played fast and loose with mind-tricks because he was tuned to the "living Force."