Never ever confuse a stock's price with the stock's value. This should become the investing motto of every investor. Traders and speculators, you're exempted.
Price will always be what pay for a stock, while value is what you will get from the stock.
Efficient market hypothesis aficionados will naturally disagree with me and that's okay, because we're each approaching the market from different perspectives.
So, if a stock is currently selling on the market for $50 a share versus the $75 it should be selling for, based on your conservative discount cash flow model, which of the two prices would you think to be the "right" price?
Again, keep in mind that price is simply whatever something is purchased for.