PSA that shouldn't need to be said: If you're explaining something with a toy model, something from 101, whatever, that does not mean you neglect the complexities of life beyond that model. Obviously life is more complex than 101 models, but they're valuable. Krugman:

In case you were unaware, Krugman has been a long-time advocate of simple sanity checks on complex models, and on using simple models to grok concepts before building up to more complicated modeling endeavors. He's right to do that! Link: