The Very First Thing I Should Have Done

I sat there and watched as my wife's wildly successful business venture: Mini Munchkins took off like a rocket. I was there to move things, take money and mainly see how it is done. It didn't take long before I decided that I had to do something similar. We attended a lot of special outdoor events and I saw all of the long lines at the food vendors and thought, man, I could make a killing doing that and I already know all about these outdoor events, so what could possibly go wrong?
The VERY first thing I should have done is figure out how much money I could make in a single day if I worked as hard as I could and sold as much as it was possible to sell, and decide if that was worth the work. Too late I realized that if I sold a bag of donuts and a cup of coffee to a person every minute of the 12 hour day and then paid the bills and split the money with my partner....let's just say it wasn't ever going to be worth it.
Real world: People don't drink coffee and eat donuts all day long, and sometimes it rains and you don't get refunds from the shows for rain-outs.
It was worth it though, because I now look at things that look wildly successful in a whole different way....