When writing code, it's important to distinguish between INTENT (what is happening) and IMPLEMENTATION (how things work).
❌ In the example below, intent is mixed with implementation:
users .filter(user -> user.registrationDate.isBefore(dayjs().minus('years', 1)) && user.hasPurchases()) .filter(user -> authenticationService.isAuthenticated(user));
In order to understand WHAT this code is doing, your brain has to discern INTENT from IMPLEMENTATION. You need to spend 5-10 seconds on deliberate thinking. It consumes your limited and precious brainfuel. And that's only a single method.
✅ Now, let's improve the code. Let's leave the intent visible, but implementation hidden:
users .filter(isLoyal) .filter(isAuthenticated);
It's immediately clear WHAT the code is doing. The code is not polluted with implementation details; details are hidden. Leaving only essential information and removing the noise is called abstraction. A well-abstracted code is easy to scan. A poorly abstracted code requires a lot of deliberate thinking and attention.
🧠 Remember: good code reveals intent, but hides implementation details until they are needed. Make the essence visible; hide the rest.