I think it was overconfidence and lack of fear that lead to the Great Depression. People were so confident the good times would continue to roll that they did not prepare. When the times were good they spent all the money they made on material things (like the story of Babel tells). Instead of saving and preparing for worse case scenario, they lived as though the good times would never end.
After the Great Depression -- for generations -- people saved. When I went to my grandma's house I would grimace every time I walked into the bathroom because it smelled like pee and the toilet always had pee in it. The reason is because she only flushed the toiled after a bowel movement.
I cringed when I looked in the sink because there would always be a container with dirty dish water in it. She only replaced it once a day. In this way, however, she did not waste water. She did this because she lived in the Great Depression years and knew what it was like to have no money to purchase anything, even simple things like water and soap.
She canned everything that could be canned and stored these in the basement. There was always enough food down there to last a year. And she never bought anything except with cash. If she didn't have cash, she never bought anything. She lived within her means. She was humble. She didn't buy all the stuff (material things) she wanted, but she was happy nonetheless.
She lived this way because she REMEMBERED the past. She remembered how hard life was in the 1930s, and she wanted to be prepared in case it happened again. My mom and dad were not as parsimonious as grandma, but they still paid cash for any material item, and they did not waste anything. Mom flushed the toilet each time, yet still saved dishwater.
Mom and dad did this because the were told story after story when they were growing up around the dinner table of how hard it was during the Great Depression. They were taught the lessons of the past and how to be prepared in the event it ever happened again. They taught about how to save every penny.
Many people forget. I look around and I see many people in my neighborhood with all the best toys for their kids and all the best toys for themselves: snowmobiles, tractors, riding lawnmowers, hunting equipment, bounce houses, trampolines, expensive wood swing sets.
Instead of saving money and preparing for the worst they assume the good times will continue on forever. So instead of saving, they spend $40 a week to have someone else mow and fertilize their lawns and spend thousands of dollars each year on landscaping. Instead of living humbly, they spend thousands on remodeling their homes just for the sake of remodeling.
They have a new car in their driveways every couple years and they finance it instead of paying cash for one they can afford. They sometimes even refinance their homes and put all their material things on the mortgage so instead of paying off their stuff they pay for it over the period of 30 years.
In essence, they are more interested in material things than being humble. It goes back to the battle between greed and materialism versus honesty and integrity and humility.
Look in my yard and you'll see I don't fit in. My yard is dirt and sand and my house has holes in the siding. It's not that I can't afford to do landscaping or to fix my house, it's that I find I don't NEED those things and chose to spend my money in more useful ways.
In a sense, if my neighbor lost his job he'd feel the recession full tilt. If I lost my job my life wouldn't change much because I'm living now the same as if I didn't have a job. I'm prepared and he is not. I read the story of the Tower of Babel and I do not forget the lesson learned. I did not live in the Great Depression, yet I don't take for granted it will never happen again.
If you always live as though you are in a recession it will matter less to you when it occurs. Why? Because you are prepared.
Fear is good. You should FEAR the Lord because he made us and has the final say in everything. When we fear Him we show respect for Him. When you respect history might repeat itself, it shows you have respect for history. And that's why we MUST never forget history.
We must educate. We must teach about depression. We must teach our kids how to spend their money frugally instead of creating a big debt. We must teach our politicians the same. We must teach them to read the Bible and to learn the lessons of it. Even if you don't believe in God you can still learn the lessons of the Bible, because it's all history (it may be allegorical, yet it's still history).
Then again, if you're a Bible follower as I am, you get a totally different view of fear. In the book of Isaiah (8: 11-15) a prophet warns: "Do not join in the schemes of the people and do not be afraid of the things that they fear. Remember that I, the Lord Almighty, am holy; I am the one you must fear... Many will stumble; they will fall and be crushed. They will be caught in a trap."
We must heed the warnings. We must be prepared.
So in the end we learn that FDR was wrong. He was wrong because in reality, fear is not the only thing to fear. In reality the only thing to fear is not being prepared. Thoughts.