Vader's potential...
I was speculating today... and a thought crossed my mind. This thought took my attention to a line from III when Vader is telling Padme on Mustafar that he could destroy Sidious. And then I remembered when Sidious tells Yoda that Vader will surpass them strength wise... Do you all think that Vader could overpower Sidious if he wanted to? And of course he wanted to... but why didn't he? I guess that's the question.