I still don't know how to even make a silicon transistor.
Give me an inverter and single logic gate and I can by myself recreate computing. Give me a silicon wafer and dopants and I no longer know what I am doing. The structure is 3D and also somewhat abstract and I fail to be able to maintain the mental state to understand it.
I don't understand my mental barrier. I get the abstract theory and rough physical concepts, but somehow I can't pull features out of a micrograph like Ken Shirriff can.