What did you learn today?

We started the Riding Shotgun series nearly three years ago to give folks a look at what it would be like to ride shotgun as Adam and I made our rounds as roving computer helpers/trainers. I have used the platform to share anecdotes that happened during the day, post pictures of cool computer setups, climb aboard my soapbox and yack about computer security, passwords, etc, and share tech tips and solutions I learned...