there is a thing called structural limitations, they are very important to understand in all engineering disciplines

the human brain has structural limitations

as the complexity of information it manages goes up the chances of error go up with it

if you want a reliable system you remove excess complexity and layer it into separate sections that can be reasoned about separately

it's not that a programmer can't manage all of those things, just that in practise you simply cannot manage them all at once and the more they interpenetrate the less fun is the process of debugging