At the most basic level, golf is all about hitting a ball with a stick, and watching it go. I remember my kids really catching one for the first time, and when they turned to me to make sure I was watching, I could see the joy in their eyes. It's an introduction to the game that we all may be able to remember. To me it's the beginning of the how the spirit of the game grabs you. There's no other ball game I can think of where the ball goes so far. When I hear someone talk about Mickey Mantle's mammoth 634-foot home run, it crosses my mind that even a high-handicapper like myself regularly hit longer shots.
And then you get to take that elemental joyful experience alone, out onto the biggest, most varied, most natural playing field in all of sport. And obviously both the singular "alone-ness" of the game and the marvelous venues for golf are huge components of the game's spirit. And then there are the rules that direct the game, and the way they put ultimate responsibility for following them on the player - focusing the spirit of the game on self-reliance, self-respect, and respect for playing partners and competitors.
And if you find that the behaviour of others is a sign of some diminishment in the spirit of the game, then talk to those players. Attempt to educate them. As those ads on television so eloquently say - almost doing something is the same as not doing something. Grow the spirit of the game by spreading it through your own actions.