The US market movements demonstrate how much things are tied...

The US market movements demonstrate how much things are tied together especially since so much of the value of the stock market (especially US stocks) is based on leverage / debt, or driven by high speed algo's. So anyway much of the supply of money that allows stocks to float up and down is not intelligent - more like a tsunami of QE.

For me what this boils down to is no one can be sure when the entire sea level will suddenly shift while we agonise over the ripples of tiny waves to get in and exit at the right moment. So better concentrate on the fundamentals first and stay with the well managed companies that have the goods in terms of saleable product (AVL for example!).