Or, like one of the companies I worked for, you could exercise your options, wait for a large Fortune 500 to buy them up, but then get told that your bylaws have a special provision that if the sale doesn't clear a certain amount, everyone's common shares are liquidated.

As in we got zero. Nothing. And this software is still in use in a major product.

So no, please don't trust options or exercised shares at any private company to be worth anything.

You want to get paid? Negotiate salary and laugh in their faces when they offer you options.