When a movie that was filmed in widescreen format is reduced to fit
your TV screen, they call it "pan and scan". They cut down the picture
to fit and sometimes you lose important parts of the image. For
example, you might have a tight shot on two characters talking to one
another. When you pan and scan, they will shift the picture from one
person to the other and you would miss the reactions that would be
included in the original widescreen or letterboxed format. In
landscape shots you might lose a lot of the scenery with Pan and Scan.
This is why letterboxing is considered to be better and why someone
might apologize when it was not used.

-Amanda from Seattle