[cgrusden]

This is a typical rebuttal from programmers when they don't know how something works underneath.

You are correct about "why" libraries are created.

Since, I'm assuming you're talking about Open-source libraries: what happens when theres an issue you're having and wondering why the library isn't doing what you want?

[DaCapoo]

I'd end up reading the documentation and understanding why I was using the library incorrectly. Failing that, I'd go look at how the library was implemented.

There's a distinct difference between looking at something when it's broken for the sake of fixing it and implementing every library on your own because you don't want to use the abstractions created by the programmers who came before you.

[Retric]

Think of it as Lazy evaluation. Without the need to solve some specific problem poking around a library may vary well be a waste of time. Granted, if that's what you want to do in your free time feel free, but work is about getting things done not having fun.

[e12e]

I seem to recall a statement to the effect that the number of people that actually understand how a modern Intel cpu works can be counted on one (slightly mutilated) hand.

Don't you want to know how your cpu works? What happens when you're having an issue and wonder why your code doesn't work as expected?

Depth of knowledge is good, but I think the rational choice is to know the most about the domain you're working in -- because the entire domain is already too big for any one person to fully grasp.

[GFK_of_xmaspast]

If it's a much-used library with a reputation for quality, like FFTW, I'm going to assume the fault isn't exactly in my stars here.