My favorite mistake

I'm not talking about Sheryl Crow (though she is one of my not-so-secret crushes). I graded over 70 students' homework assigments for a junior-level (of college) engineering class. I was absolutely shocked, and I got a pretty hearty chuckle, at the number of students who, when asked "How sensitive must a [specific] pressure gauge be?" answered "Very sensitive" or "Extremely sensitive." They were given some parameters and were supposed to make reasonable assumptions to come up with a number, not a qualifier!

Only slightly better were the students who said the gauge must detect a certain percentage pressure change, without specifying the initial pressure of which the percent change would be measured. It's like saying "I need a car to fit half of some stuff" but not knowing how much stuff you need to fit half of.