What Can Parents Learn from a GPS Navigation Unit?

You've typed a destination into your GPS and it has decided on a route for you.
For reasons unknown to the unit, you decide to deviate from its route.
It says, "Recalculating" and then tries to convince you to go back to the original route a few times.  It will ask you to turn right, then turn right, or to make a U-turn.  Eventually it realizes what's happening and accepts the new route.

Recalculating involves giving up its version of reality and dealing with the facts on the ground.  There are many routes and you are taking a different one.

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"Mom, I decided that I don't want to be a doctor.  I want to be a musician.  I can make a few dollars as a school crossing guard -- that'll give me time to compose music during the day.  I'll practice with the band at night."
"Recalculating.  Maybe you can take biology at night school."
"The band will be practicing every night."
"Recalculating.  If you apply to med school in the fall, you might be able to get in next year."
"We'll be on tour."
"Recalculating.  .... Recalculating.... When can I hear you play?"