1. Activities: Diving, all types of water sports
2. Dangers: Habu snakes, they're extremely poisonous.
3. Annoyances: The humidity, Monsoon season, and for some the typhoons.
4. Health: The Local's are into health and exercise, ie eating mostly raw food, running outside at all hours of the night...
5. Interacting with the Locals:  Be respectful, don't play loud music when you're driving, speak softly, dress modestly... the Japanese are respectful people if you respect them and their culture it means a whole lot. Also, try to learn the language that means so much to them.
6. Transportation: The taxi's are always available, they do not accept credit cards here on island, mainland Japan taxi's do, but not here. If you are in the Marine Corps the Green line buses are available free of charge.