Social courtesies are often fairly formal. In particular, when drink or food is served, it should not be touched until the host invites the guest to do so. Never pass or accept anything with the left hand. Indonesians are polite and will extend endless courtesies to visitors whom they trust and like. Informality is normal, but a few smart establishments encourage guests to dress for dinner.
Safari suits are acceptable on formal occasions and for business wear.
Muslim customs, especially those concerning female clothes, should be observed.