[Pauan]

The whole point of an abstraction is to remove complexity for the user.

So I assume you mean "implementation complexity" but that's irrelevant, because that cost only needs to be paid once, and then you put the abstraction into a crate, and then millions of people can benefit from that abstraction.

[brundolf]

You've got a very narrow view that I'd encourage you to be more open-minded about

No abstraction is perfect. Every abstraction, when encountered by a user, requires them to ask "what does this do?", because they don't have the implementation in front of their eyes

This may be an easy question to answer- maybe it maps very obviously to a pattern or domain concept they already know, or maybe they've seen this exact abstraction before and just have to recall it

It may be slightly harder- a new but well-documented concept, or a concept that's intuitive but complex, or a concept that's simple but poorly-named

Or it may be very hard- a badly-designed abstraction, or one that's impossible to understand without understanding the entire system

But the simplest, most elegant, most intuitive abstraction in the world has nonzero cognitive cost. We abstract despite the cost, when that cost is smaller than the cost of not abstracting.

[Pauan]

Even the costs you are talking about are a one-time cost to read the documentation and learn the abstraction. And the long-term benefits of the abstraction are far greater than the one-time costs. That's why we create abstractions, because they are a net gain. If they were not a net gain, we would simply not create them.

[pkolaczk]

The whole point of abstraction is to replace the need of understanding all the details of the implementation with a more general and simpler concept. So while the abstraction itself may have a non zero cognitive cost for the end user, this cost should be lower than the cognitive cost of the full implementation that the abstraction hides. Hence the net cognitive cost of proper abstraction is negative.

Abstractions allow systems to scale. Without them, it would be impossible to work on a system that's 1M lines of code long, because you'd have to read and understand all 1M lines before doing anything.