As you develop as a programmer, IMO, you begin to see different practices, different Algorithms, and "more than one way to do it". Seeing this code can be a great learning experience for you, even though you did not write the code. But is doing this only going to confuse you?

For example, let's say you have a library in any language that was created by a colleague, and you have been using it for a while. You decide to look at the actual source code, regardless of how extensive it is, and get a better look at how this library is written. For the sake of example, the function you use most often from this library is the max function, which finds the largest of two numbers. But this function is a lot more complicated than it needs to be. The way it is written is confusing the heck out of you, and you don't know how this works.

Will this make you a better programmer, because you realize how complicated it is for such a simple function, or will it make you a worse coder because you feel less confidant?

So my question, in general, is does reading source code make you a better programmer and if so how? If not why do people still do it?.