I remember in middle school my math teacher telling us that people should check the tax rates before accepting a raise, because it might put them in a higher tax bracket and really they’d *lose* money.
(I also had a math teacher in *honors* geometry tell me that the only reason pi is irrational is because we can’t make circles or rulers perfect enough to measure it; one day we can measure circles with lasers and we’ll know the correct value of pi…)