See if I find myself to have another front open for research through my last research, than I get satisfied, as life & research is a journey not a destiny
I hope this is still in-complete answer, due to running short of time, please accept my apologizes
Well yes I am satisfied every time I does some research, I find some-other question pop up and then I try to find the answer to it.
And yes many times or usually I get defeated, but what I like the most, is that, there is plenty of scope to improve, as improving leads to build yourself, introspect, self control and grow yourself, it is a chain which leads to the answer of some questions and let us to find answers to some questions which were still unanswered.