Continuing with inventors we love, we've finally hit on a guy that was an amazing engineer and inventor but just terrible at marketing and entrepreneurship in general.

Enter Nikola Tesla. Without him, we basically would still be living in the dark, or with a powerhouse ever mile to turn the lights on. Sure, he wasn't real good at the business side of things, and he did end up going crazy and talking to pigeons, but that doesn't mean he didn't have a huge impact on the world.

Did I mention that he was thought to be working on a death ray as well?! Yeah, you'll probably want to learn all about his life right here.