IMHO, market sentiment plays at least as big of a factor in share price as anything else. Quite a few years ago I did OK by being a bottom feeder on stocks as bad news hit the company. First it was Bausch and Laumb who had eye drops that gave people a fungus. Oops, their shares plummeted, but when you think about it...B&L's eye drop part of their business was a very miniscule part of their portfolio (optics, glasses, contacts, etc). So I bought shares of them and within a few months their price recovered nicely. Same thing with Marth Stewart's Home Living when she went to prison. Again, good company overall, so after the shares seemed to hit a bottom as she went to jail, I bought it only to watch it recover in about 5 months. There were a couple others in similar fashion that I did ok on. Then my ex talked me into buying Crocs. Bad idea...as was my choice to buy Owens Corning near the end of the asbestos litigation. You win some, you lose some.
Maybe my vision is going bad, but I don't see opportunities like this nearly as often nowadays.