Because honestly, when the United States broke apart from the British in 1776, over time, our revolutionary war inspired other people that wanted to form their own countries & to seperate from the big 'ol countries that have them as colonies, or as pronvinces. It showed that the little man can beat the big man in its own territory that it wishes to gain Independence on.
Essentially, the United States said, "See ya later. You treated me like I was nothing to you, you took advantage of me and only wanted my money!"
Then Britain was something along the lines of, "Hah! You think I care?!"
Then the United States had had enough of the mercantilism and the enrichment of the mother country and all the taxation without representation and made the "break up letter."
