Final answer:
The Proclamation of 1763 upset colonists because it limited their westward expansion, which they viewed as a violation of their rights. This restriction was seen as an infringement on their ability to pursue economic opportunities.
Step-by-step explanation:
The Proclamation of 1763 upset colonists because it limited their westward expansion.
The proclamation forbade colonists from settling west of a line drawn along the Appalachian Mountains.
This angered the colonists who had fought on behalf of Britain in the Seven Years War and expected to be able to settle on land taken from France.
The restriction on westward expansion was seen by the colonists as a violation of their rights and an infringement on their ability to pursue economic opportunities.