I think that joke is quite harmful because in the process of going and breaking down the system to access the computer can crash the server thinking that the hacker is a virus that it can't delete so it crashes and bam! That server will never work again! Hacking is quite a problem these days. Hacking or cracking can break down computers and fry them also may cause identity theft. So with no barriers around the computer anyone can hack into your computer without any problems and steal information personal. Also as i forgot to mention was that if hacker tries to hack your computer and messes around your computer like a toy the computer will light up in fire and maybe burn or explode.

Teens might hack for revenge or maybe it's because they are just trying to be smart or just pulling a prank. Computer hacking is illegal because even though they do not steal info. they might put viruses into your comp and bam your comp. fries.