Check out this abridged history of hacking.
The history of mankind: there is always someone out there who is interested in getting access to other people’s ‘stuff’. While many of the examples given in the post focus on government systems, that’s not the rule. Breaking into a military system is always a thrill (and embarrassment to the government), but breaking into company and personal accounts is more lucrative. Systems can be hacked, so it is YOUR responsibility to take care of your personal data. Strong passwords are a requirement for protecting your personal data.
Also very interesting is the type of people who are doing the hacking. You may not have seen your Aunt Sally in the list, but a lot of those teenagers and students could have lived just down the street from you. Make sure that you are securing your passwords.