Show vs. Tell

Over on Facebook, a friend asked "is it always poor writing to tell and not show?" Here's my reply:

If you had an entire story that was nothing but "show" it would be overlong and tediously detailed. I interpret the maxim of "show, don't tell" as applying to the most important parts of the story: the characters' motivations and emotions, the key bits of worldbuilding, the pivotal moments of the plot. When the character is only driving across town? It's okay to just tell us that part.