Golf is definitely cool. Part of being cool is a certain amount of nonchalance, which the game of golf traditionally values. It's not really appropriate behavior to throw f-bombs all over the place when you hit a poor shot, nor is it appropriate to shout in exuberance when you make that long birdie putt.
In the former situation, you're supposed to just brush it off like it's no big deal. In the latter, you acknowledge your partners' congratulations graciously. In either case, you don't show your emotions, and that's part of what being cool is all about.