"You don't understand, you just know how to make it work" -- Computer science professor.

@nixCraft Haha, that’s a famous example from the famous Jargon File:
“A novice was trying to fix a broken Lisp machine by turning the power off and on.

Knight, seeing what the student was doing, spoke sternly: "You cannot fix a machine by just power-cycling it with no understanding of what is going wrong."

Knight turned the machine off and on.

The machine worked.”

See here: http://magic-cookie.co.uk/jargon/mit_jargon.htm - warning! Highly addictive reading!