Originally Posted by Tadao
I hear that Spirit hasn't done jack shit.
That's "Jack Schitt". One of the Schitt brothers.
Actually, Spirit has
done Jack, from the perspective of analytical science. Mostly it confirmed all the crazy stuff that Opportunity fell into (literally) making the findings from both rovers much more credible, and giving some more insight as to Martian geomorphic history.
On the engineering front, the problems encountered and experienced by Spirit made the JPL scientists devise workarounds that were innovative. Eventually this learning will advance the development of future rover missions to Mars, and perhaps beyond.
Strictly speaking, there have been very few original discoveries by Spirit, so in a pure sense, you are correct.