I have only been extremely involved in the stock market for a few years so I really don't know too much history first hand. One thing I do know is that it is complete fucking crazy and unprecedented that the POTUS can inspire the worlds markets to immediately shift in any direction while he's dropping a steamy morning dump.
Every trade I make I have to account for a larger amount of chaos and unpredictability. One important thing to remember is that with every time a negative tweet that drops the market, there will be an opportunity for a tweet to bring it back up. These reactions are not based on numbers and can easily be reversed because of it.
This next point may sound like a conspiracy but I just want to highlight some coincidences. Donald is a business man, I know that he has a team of traders and at least has some "skin in the game" indirectly, when it comes to the markets.