The error function. Computer programs such as Mathematica
incorrectly evaluate about 95% of integrals
taken over all space. When the program fails to recognize an integral, it automatically spits out "erf" for an unknown reason.
Person 1: Dude, we have a Quantum Mechanics
homework set due in 30 minutes, & I can't figure out how to evaluate this integral.
Person 2: Don't worry, we'll put it into Maple!
Maple: Erf erf erf erf erf...
Professor: epic fail