My Dad was among the oldest of 12 children. After getting through sixth grade, he had to get a job to help support the family.
He was pretty good at laying bricks, so someone came to him looking to build a chimney. Now, Dad knew that this guy had a habit of hiring someone to do a job and skipping out when it came time to pay the bill... but he needed the money so he built the chimney anyway.
As he expected, the guy wouldn't pay up. So my Dad waited for the weather to turn cold. Once again, as he expected, along comes the payment-dodger complaining that the chimney won't draw. Dad says "if you pay the bill, it'll start working". Finally the guy pays up.
Dad goes over to the guy's house, climbs up on the roof and drops a big rock down the chimney. Turns out Dad had inserted a sheet of glass about one-third of the way down the chimney.
Just goes to show that street smarts are just as important as book smarts.
Way to go, Dad. I miss you.