I had a bit of an aversion to the premise of the book at first, because it seemed manipulative to me somehow ("winning" and "influencing" people, ie. thinking of them as systems and trying to "hack" them) but I eventually came to see how narcissistic that was--I am not superhuman and cannot exert mind control, so any social "hacking" is really just using the system the way it is designed to be used. At the end of the day, most of Carnegie's advice boils down to being a nice person and putting yourself in other people's shoes often, but with examples of how that sort of behavior can be beneficial to you.
Spot on. Reminds me of the the quote by Cisco founder Sandy Lerner: "The first rule of any game is to know you're in one."
I would add that the second rule to any game is to know the game is broader than what it seems. Poker is really not just about cards. Startups aren't about building a product. Passing an exam isn't about knowing the answers. Thinking about the broader game opens so much more opportunity than being stuck in what people believe is the game's limit.
When I look at leaders, the thing that I see more and more is the ability to not stress out about situations. Coming up with solutions is less important; putting everything in perspective is the key. Much of this comes down to empathy and being a nice person, as you describe.
By showing interest in what other people are doing instead of only telling them about yourself or espousing your opinions they are more likely to want to be around you.
1: http://en.wikipedia.org/wiki/How_to_Win_Friends_and_Influenc...