A lot of hacking is actually social engineering. It's not hard to get a tech-illiterate person to give up their password, and that's the softest target for an attack.
There are usb sticks that can kill your pc by getting charged and then discharging all the electricity at once to your pc so no sandbox will save you in situations like those.
Or even jaded tech savvy people. I work in IT and there have been a number of times that I have witnessed or heard about people who know better causing an incident because they're burnt out or irate.