In the short run the market is like a voting machine and in the long run it is a weighing machine. Just really understood this today. The weighing machine is never wrong! So in the long term, the market will get it right. From Joel Greenblatt:

• Over the short term, Mr Market acts like a wildly emotional guy who can buy and sell businesses at highly depressed or highly inflated prices.
• Over the long run, Mr Market gets it right.

So if do have bad stocks, be scared that Mr Market will get it right soon enough. :(