A good dive buddy knows the importance of staying in close range and view of their buddy. This allows for good communications underwater and in the event of an emergency action to be taken without delay. So it should be unless you know the buddy you will be diving with, communication before the dive of each others abilities, training, expectations during the dive, a review of signals and each others equipment. Listening to the dive briefing and then discussing anything needed between buddies. A complete buddy check before hitting the water and a quick check before submerging. A good diver is always learning and that improves their abilities and value as a buddy.