In the heat of congressional negotiations, the small stuff occasionally gets overlooked. But even by normal congressional standards, Howard Gleckman and the rest of the team at the Tax Policy Center have found a doozy. The "fiscal cliff" deal, as you may recall, kept the Bush tax brackets with the exception of a new 39.6 percent bracket on income over $400,000 for singles, or $450,000 for married couples.

But the old top bracket of 35 percent only kicks in at $398,350. For married couples, that means the 35 percent bracket covers $51,650 in income — not a whole lot, but a fair bit. But for single people, it covers a measly $1,650. That's the smallest bracket in the income tax code, so small that TPC calculates that fewer than 500 single people will face a top rate of 35 percent.

Then again, not many people are dealing with rates above 25 percent, period, as the latest TPC data shows: