Why did the colonists shouted no taxation without representation?

a phrase, generally attributed to James Otis about 1761, that reflected the resentment of American colonists at being taxed by a British Parliament to which they elected no representatives and became an anti-British slogan before the American Revolution; in full, “Taxation without representation is tyranny."

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.

it is on the verge of happening but the process can take a while

explanation: