Nombrilliant, – On Being Middle Aged

  In theory
  there's no difference between theory and practice. 
  In practice, there is...
  but you try telling that to the young people today
  and they won't believe you. Nope.

(apologies to Brewster/Feynman and Monty Python).

I think there is a 4th phase corresponding to a quiet Zen acceptance:

1. Naive simplistic enthusiasm for clear abstractions (may call them beliefs ). Fan boy evangelist. Probable burnout.

2. Pragmatic contact with the real world. Humble practical craftsman. Effective, productive, quiet, accomplished.

3. Wide knowledge of multiple domains, previous mistakes, leaky abstractions and blind alleys. Over-confident narcissist guru (usually management consultant), depressed blathering doomsayer (usually has their own seat at the far end of the local bar), perhaps both.

4. Quiet acceptance that offered advice is never heeded: everyone needs to make their own mistakes. Encourages action, exploration and failing fast. Never says what should be done, but always steers youngsters to answer that question themselves. Smug simmering silence or aphoristic elliptical oracle. Resignation, or perhaps depression, at having conquered so few trifling insignificant projects in a whole lifetime, but now the ultimate deadline is approaching.

If the author contains a quantity of wolves, at least one has the heart of a poet.

However, the disrespect to Scala enthusiasts! Scheme enthusiasts are so much worse.

There's a danger of becoming the old man yelling at clouds.

OTOH, the OMYAC often has a point, that the yoof can't quite see.