For some reason, people take their cues from price action rather than from values. What doesn't work is when you start doing things that you don't understand or because they worked last week for somebody else. The dumbest reason in the world to buy a stock is because it's going up.
If you expect to continue to purchase stocks throughout your life, you should welcome price declines as a way to add stocks more cheaply to your portfolio.
When a management with a reputation for brilliance tackles a business with a reputation for bad economics, it is the reputation of the business that remains intact.
The best business returns are usually achieved by companies that are doing something quite similar today to what they were doing five or ten years ago.