I think this most captures Don. And the point "right now it's Sally" is important too because to him the people that he cares about seem to change. The only one who seemed consistently important to him was Don Draper's wife.
This guy turned his back on his own brother, and seemed very little effected by his brother's suicide. It is interesting on the occasions that he does something nice for people, like going to see Peggie after she gave birth, or paying Pete's share of the new company. This from the same guy who twice almost disappeared from his two kids.
Originally Posted by Piobaire
Don does not care what 99% of the people in his life think about him. A great example was a scene between him and Peter where Peter says something about how he's always thinking about Don's opinion of him and Don replies he never thinks about Peter. That's the truth for almost everyone in his life. It's when one of the few people that does matter to Don what they think about him takes a turn for the worse he loses it. Right now it's Sally.
So to ask if Don cares what people think about him or not, is as usual, a far too simple question. There is the vast majority of people, which are almost mere objects to be manipulated by him, and then the very few people who's opinion of him he values.