Over the long term it has paid to be an optimist when it comes...

Over the long term it has paid to be an optimist when it comes to macro economic issues. The pessimists get it right every now and then but they lose a lot of money waiting on the sidelines or funding their short positions for much longer than is economic. As the market gets more expensive it pays to build up the cash proportion of your portfolio to take advantage of declines (as we see Buffett doing right now), but trying to time the market by getting out altogether is a fraught strategy, especially if you are realising big capital gains tax liabilities in the process.