You do know that the global economy is doing quite well, right? Furthermore, the economy is actually in danger of getting overheated, which is why Yellen is raising interest rates. This has been a concern of hers for the past two years, it's nothing new. There are so many nuances regarding the state of the economy I won't pretend to understand it all but I sincerely doubt that two months of an erratic president could cause a great boom to the economy, especially when the economy has been doing well the last 6-7 years and this is in line with a global trend. In fact, I'm worried that Trump will cause too great of booms in the future with his absurd "pro-business" policies. The thing about "pro-business" policy is that it benefits business in the short term, which is fine with CEOs because they only have to have a short term success to acquire massive amounts of wealth. If Trump replaces Yellen in two years with someone who won't responsibly raise interest rates when the danger of inflation hangs over the economy, we could see another crisis similar to the housing crisis at the end of Bush's second term. That's the danger of deregulation. You create a boom-bust economy. Reagan did it in the 80s, Clinton did it in the 90s, Bush in the 00s. Obama was the first president in my lifetime that didn't fall for the laissez-faire bullshit and it was the first period of steady, gradual growth. The boom-bust works out great for those who acquire millions during the boom. For everyone else, it's a rollercoaster you're not strapped into.
Your generalizations about optimism and taking risks are exactly what has caused all the busts in the past. Optimism is fine but that's not what happens during a boom. What happens is irrational overconfidence and that leads to horrible consequences.