Cell phones

Do not carry on loud cell phone conversations if you are around other golfers, in the clubhouse, or near a tee or green. If you must take a call, do so discreetly. Turn down your ringer, put it on vibrate, or just turn your phone off. Golf is meant to be a relaxing, enjoyable game. People come to play golf to get away from the rat race, or to enjoy the company of others. Be considerate, don't ruin someone else's experience.

This goes for practice greens and driving ranges, too. Practice requires concentration and diligence, and you wouldn't want someone to see how far they could drive your cell phone, now would you? Some clubs have banned them completely, others allow their use in specific areas. It pays well to know the rules at your club.