Show, don't tell

The problem with "show, don't tell" is all of the assumptions you have to make about what you are showing. You have to hope your reader interprets things as you have done, a quite naive point of view in a world of psychological and other complexities, and will too often find yourself at least tempted to try to coerce the reader into sharing not only the reading you intend but the assumptions that underlie them and upon which they depend. Sometimes a greater (and more honest) verisimilitude can be achieved by more directly orienting the reader to the parameters of your particular story, even if this must involve a greater amount of "telling."