[wst_]

I do agree with you completely. But the problem here is as old as programming itself. It's not always easy to define function boundries.

If your function returns pizza, as mentioned in other comment, adding some toppings won't change the boundaries. It still returns pizza, with peperoni or not. It doesn't change how you make the pizza. You're just adding more data to it. You may solve it with syntax, language data structures, etc. Whatever you like to make it more readable to the caller. But probably you'd want to pass toppings in arguments.

On the other hand if you have a boolean param that changes how function works. That's questionable in my opinion. Say you want to return list of users from DB but omit interns, sometimes, and you need to call API (or query DB) to know if someone's intern. You could define `omitInterns` bool argument but it seems clunky to me.

I may be mistaken, though. As said: defining boundries is not easy.

This also touches other problem a bit. Should we strive to decrease `if` branching in our functions or not? I personally tend to branch very early on, so later I can follow straight path. That's not always possible, but if it is, it helps greatly. Makes code easier to follow.