And I'm not talking about Trump's inauguration yet. Well, maybe that's part of it. My actual subject is my reaction when I saw the first homework assignment in my Astronomy class in Dynamics and Hydrodynamics. Of course it wasn't based on the class material, since there wasn't any yet. Instead it was more of a basic math pretest: Differential equations, analyzing the behavior of integrals and deriving vector identities - stuff I hadn't done, for the most part, in fifty years. I panicked when I couldn't see how to get the inhomogeneous solution to the very elementary first differential equation. It reminded me of the feeling I had when I first saw the problem set on my PhD comprehensive and realized that there was not a single problem on it that I knew how to solve.
However, just as on that long ago comprehensive, once I pondered the problems a bit I gradually realized that I did have the tools, in this case rusted, dull, and buried deep, for solving the problems. In fact there was a lot of joy in finding out the pleasure of doing math.
Of course I'm still pretty horrified at the other first day assignment, writing a parallelizable program to analyze the interactions of hundreds of thousands of stars or planetoids interacting under gravity. It's been a long, long time since I wrote code, and I never used modern parallelization stuff.