Grover Norquist and his anti-tax pressure group Americans for Tax Reform, which fears that if taxes become less annoying voters might be less unhappy about paying them. After all, if the government did something to make your life easier it would be harder to tout the difficulty of tax compliance as a reason to abolish the progressive rate structure.

Grover Norquist and H&R Block: The unholy alliance of tax prep firms and conservative activists to make your taxes even more complicated. - Slate Magazine