Thou shalt not expect to find all things precisely as they are at home. Thou hast left home to find things different.
Thou shalt travel in a spirit of utter humility. The fact that people may think, speak and act differently does not make them inferior.
Thou shalt not let thy travel companions get on thy nerves, for thou art paying good money for this experience.
Thou shalt not worry about things at home while thou art away, for he or she that worried hath little joy.
Thou shalt not judge all people of a city or a country by one person with whom thou hast had a problem.
Thou shalt remember that endless waiting lines, delays, cancellations and bad food are a part of traveling, and thou shalt smile and not complain.
Thou shalt not expect or demand that everyone speak English.
Thou shalt carry thy passport on thy person only when necessary, for it is a valuable document and prime target for thieves. When in possession of said document, it shalt be hidden under thy clothing; it shalt not be carried in purse, pocket or backpack.
Thou shalt not litter or in any way spoil the places thou shalt visit. Take away only thy memories; leave behind only thy smile.
Thou shalt not make promises to the people you meet unless thou can follow through.