Agreed. Electronics hackery, especially making sense of someone else's circuit, takes a lot of acquired knowledge. Knowing common circuit topologies and being able to identify them when you see them, knowing that if you see a component in a TO220 package there's a 95% chance its either a transistor or a linear reg (usually you can guess more specifically just from its location on the board), having a mental list of components you can use to design a certain circuit (hmm, an audio preamp? I wonder if an NE5532 would be suitable?), knowing that a yellow bipedal surface mount thing is almost certainly a tantalum cap, knowing that a number of connectors near a SoC is probably JTAG etc. All of this just comes from experience and recognising patterns! Although I imagine dealing with code is somewhat similar? Perhaps there are certain things which you come to notice by instinct? Eg maybe you can look at some assembly and, just skimming over it know that it's supposed to be a time delay?