The United States Code -- containing federal statutory law -- is more than 50,000 pages long and comprises 40 volumes. The Code of Federal Regulations, which indexes administrative rules, is 161,117 pages long and composes 226 volumes.
No one on Earth understands them all, and the potential interaction among all the different rules would choke a supercomputer. This means, of course, that when Congress changes the law, it not only can't be aware of all the real-world complications it's producing, it can't even understand the legal and regulatory implications of what it's doing.
There's good news and bad news in that. The bad news is obvious: We're governed not just by people who do screw up constantly, but by people who can't help but screw up constantly. So long as the government is this large and overweening, no amount of effort at securing smarter people or "better" rules will do any good: Incompetence is built into the system.
The good news is less obvious, but just as important: While we rightly fear a too-powerful government, this regulatory knowledge problem will ensure plenty of public stumbles and embarrassments, helping to remind people that those who seek to rule us really don't know what they're doing.