Business idea and feedback thread

I was reading the potential gatorade-esque business idea thread @daychilde put up the other day and it got me thinking about all the potential business ideas my partner and I have been kicking around. I'm hoping folks can post their prospective business ideas here and folks within those industries and provide feedback, insight, or hurdles to the ideas. Kind of like the hobby thread from a few weeks ago. Excited to hear what everyone is thinking about!