Doing my own color is one of the things that's made me a better cinematographer. It meant that whenever I screwed something up on set, I was the one who had to fix it in post... so I had front row seats on finding (and fixing) my own blunders... so on subsequent shoots I'd remember those blunders and avoid them.
Nowadays I use power windows a LOT less than I used to, because I learned to sculpt and control light a lot more on set because having basically screwed myself, I knew what to look for the next time around.
Of course there are always new ways to screw things up, and when you end up shooting one scene in two parts split two months apart (we needed the waterfall to change its volume drastically during the scene, so...) or when you film one of the actors 80 miles away and in completely different light (the elk didn't get the call sheet) and have to match those it's still work, but for me lately that sort of extra work is a lot more common than, "Ah crap, I should have flagged the light off of that wall back there."
I honestly think I've learned more about cinematography by studying color grading and editing than I have from any cinematography oriented class/seminar/etc I've taken.