Just thought you'd enjoy this -- from "Etiquette in Society, in Business, in Politics and at Home," by Emily Post (1922):
Golf is a particularly severe strain upon the amiability of the average person’s temper, and in no other game, except bridge, is serenity of disposition so essential. No one easily “ruffled” can keep a clear eye on the ball, and exasperation at “lost balls” seemingly bewitches successive ones into disappearing with the completeness and finality of puffs of smoke. In a race or other test of endurance a flare of anger might even help, but in golf it is safe to say that he who loses his temper is pretty sure to lose the game.
Golf players of course know the rules and observe them, but it quite often happens that idlers, having nothing better to do, walk out over a course and “watch the players.” If they know the players well, that is one thing, but they have no right to follow strangers. A player who is nervous is easily put off his game, especially if those watching him are so ill-bred as to make audible remarks. Those playing matches of course expect an audience, and erratic and nervous players ought not to go into tournaments—or at least not in two-ball foursomes where they are likely to handicap a partner.
In following a match, onlookers must be careful to stand well within bounds and neither talk nor laugh nor do anything that can possibly distract the attention of the players.
The rule that you should not appoint yourself mentor holds good in golf as well as in bridge and every other game. Unless your advice is asked for, you should not instruct others how to hold their clubs or which ones to use, or how they ought to make the shot.
A young woman must on no account expect the man she happens to be playing with to make her presents of golf-balls, or to caddy for her, nor must she allow him to provide her with a caddy. If she can’t afford to hire one of her own, she must either carry her own clubs or not play golf.