Do you find your household thermostat to be endlessly fascinating? How about that smoke alarm installed in your basement — spend much time gazing at it with wonder? Tony Fadell did. The founder of Nest has had a lifelong penchant for looking at mundane everyday household devices and wondering Why hasn’t somebody improved this thing? That tendency led him to reinvent the aforementioned gadgets — and recently resulted in a $3 billion payday, when Nest was acquired earlier this year by Google.