The colonists were upset because of not only the unfair treatment, they were also upset because the British had unfairly and unreasonably taxed their tea (a beloved drink at the time) The colonists had decided it was time to act so they decided to dress themselves up as Native Americans (unfairly called savages at the time) and when their shipment had come, they boarded the ship and threw all the tea overboard. The outcome was as to be expected but it got the message that the colonists were trying to send, through. Parliament was outraged and passed the Coercive Acts.
