When entering a yard Haitians shout out onè (“honor”), and the host is expected to reply respè (“respect”). Visitors to a household never leave empty-handed or without drinking coffee, or at least not without an apology. Failure to announce a departure, is considered rude.

People feel very strongly about greetings, whose importance is particularly strong in rural areas, where people who meet along a path or in a village often say hello several times before engaging in further conversation or continuing on their way.

Source: http://www.everyculture.com/Ge-It/Haiti.html