The top 10 reasons to scrap the tax code. They're all valid, but I think this is the most important:
10. Laws Should Rest on Principles of Justice
The tax code is modified every few years along no reasonable principle. The code is arbitrary and unpredictable, and is morphing from its stated purpose-- efficiently raising government revenue-- into an instrument that Congress uses to instill fear, punishment, and political control. The code should be scrapped and replaced with a more just system based on principles of fairness and equality before the law rather than on the whim of lobbyists and lawmakers.
You could pick almost any of the other nine as equally important. But the way the government uses the tax code to direct our lives in all sorts of capricious and often indefensible ways is what takes the code furthest away from the simple purpose of raising money.