Here is an example of what happens when someone is tempted to use their hacking skills for evil. Hopefully it goes without saying, but do NOT try this one at home.
When his wife asked for a divorce [Andrew Castle] obviously did not like the idea so got busy building himself a DIY electric chair, placing a metal chair in his garage he wired it up to a 240V 13 amp wall output with the intention of luring his wife to sit in the chair for “a chat”. Fortunately the story ends as well as any story involving something as foolish as a homemade electric chair can end. We are guessing that [Andrews] wife’s suspicions were initially aroused when she was invited to sit in the lone metal chair in the garage, whilst he stood behind her holding a rubber cudgel. After a brief struggle she managed to escape unharmed and [Andrew] is now facing 10 years in prison.
All questionable morals aside, from the brief description available it looks like there may have been a few holes in the logic (or lack of) behind the construction of the chair, for one circuit breakers come to mind.