You should not need to read every line of code in every file and function to understand what’s going on to the level you need to solve a particular problem. You must make a decision to NOT look deeper at some point on any non- trivial code base. A good program with good names and comments in the appropriate places is what allows you to do exactly that more easily . When you see sort(usernames) in the middle of a function do you need to dive into sort to be able to understand the code in that function?? Probably not, unless you are fixing a bug in how usernames are sorted!

With that said , get good at jumping into definitions, finding all implementations, then jumping back where you were. With a good IDE you can do that at the speed of thought (in IntelliJ that’s Cmb+b, Cmd+Alt+b, Cmd+[ on Mac). I only open more than one file at the same time when comparing them. Otherwise it’s much easier to jump around back and forth (you can even open another function inline if you just want to take a Quick Look, it’s Alt+Space). Don’t use the mouse to do that, things you do all the time can be made an order of magnitude faster via shortcuts. Too many developers I see struggle with that and are embarrassingly slow moving around the code base!

The problem is, most of us are working in business logic, and I have never been in a company (have been to 5) where you don't have to look into the details. Not only did I need to look at the details, I also needed to read the comments to understand why there is a +0.024 in the code.

This is why I want to get into system programming. At least less business logic. They are still going to be complicated, but I feel it's a lot nicer to, e.g. go from the bottom of the process struct than the bottom of some half-ass business stakeholder!