Nothing makes teenagers want to do something so badly as being told they can't. Attempting to bypass school computer security was one of my earliest forays into understanding computers.
Not only teenagers. I was 7 or 8 (~1990) when my dad told me not to use our home PC without his supervision and under no circumstances should I start Norton Commander. The next day when he was at work, I booted the PC, started Norton Commander (I observed that he typed 'nc'), and tried every possible function that I could find ;).