The Internal Revenue Code really isn’t complicated at all; it’s very bare-bones. The IRC is the primary, codified tax law. Things get difficult because the IRC must be read in the context of volumes of regulations, revenue rulings, revenue procedures, IRS notices, IRS announcements, Treasury Decisions, and case law.
As some people have mentioned, much tax complexity relates to somewhat obscure, and more complicated, transactions. The more sophisticated or unusual the financial activity, the less simple the tax treatment.
But, average, middle-class and lower-middle-class taxpayers also face their fair share of confusion. This is because of America’s bizarre, prevailing attitudes about not raising taxes or providing services that are routine and expected in other wealthy, developed countries.
Example—In many countries, post-secondary education is free. In the U.S., free college or university is unheard of; a private school costs $55K per year, and state schools, although less costly, are still expensive. So, the U.S. has an impossibly elaborate system of tax credits and deductions for educational costs and student loan interest. Why make things easy—just extend free public education beyond high school—when they can be convoluted beyond belief?
Example—Most developed countries offer free preschool and daycare for young children. In the U.S., working parents are on their own. They scramble to find decent child care and then try to benefit from a maze of tax provisions. If they’re lucky, their employers will let them take $5,000 of salary, on a pre-tax basis, to apply to child care costs.