My first unintentional "hack" was in middle school, I had been programming for a couple years already and I was really bored.

My school had blocked facebook, twitter and so on because most students are lazy and think everything revolves around their "descrete" cleavage picture's likes. Any way, I thought most would be naive and desperate enough to fall into a "Facebook unblocked" app at the desktop, the program was fairly simple just a mimicking FB page done on C# ASP that saved user and passwords in an encrypted file.

I distributed it in around 5 computers and by the end of the month I had over 60 accounts, and what did I do? I used it to post a gay relationship between two of my friends on fb (one had a gf), it was dumb but boy did I laughed, after that I erased everything as it didn't seem so important.