It helps to know about a few key details:

Gravity

Halting problem

Travelling salesman & NP-hard

CRUD

Gödel's incompleteness theorem

Kolmogorov complexity

Series by Richard C. Waters

Simple finite groups

Projective geometry and octonions and complex numbers

Soldering electronics

Transistors, resistors, capacitors, coils, and diodes

Linear Algebra

Statistical Calculus (step functions and Ito integration)

Exponential function

Gamma function

Table saws

Screws vs nails

You want a nice little ball of knowledge with a comparatively large surface that you can attach stuff to. And then you also know what kind of expert to get.