I would have found it very difficult to understand recursion if in the past I hadn't dabbled with Zilog Z80 assembler. Knowing what call and ret pushed on and popped off the stack has helped me get to grips with the concept of a sub calling itself. When I've tried to explain it to other people I always get blank looks.

In engineering the difference between skilled and unskilled is not only knowing what to do but why it is done that way. I remember a tutor explaining it was the difference between training and education.

Which reminds me, if you tell an engineer something is broken they will inevitably strip it, clean it, oil it where appropriate, rebuild it and then see. With electricians in particular (they have magic cloths!), this is often all that is required.

Having some idea of what's going on under the bonnet is _good_.