From what I read above, it sounds like you think a librarian is not ambitious, but being a library director is? Why? Simply because the library director has reached the apex of their particular ladder? Would not this mean that anyone who did not desire to be the CEO of their company was a slacker, as well? I would also point out that the amount of responsibility that the librarians in my university library carry far excels the responsibility of the director of the small public library where I started my career. Was she somehow more ambitious than they?

In my experience, library directors of larger libraries must give up their passion for librarianship. They become administrators. I have no aspirations of becoming an administrator, so I suppose I am a slacker. I admit, creating budgets and long range plans, attending meetings, managing the petty grievances of personnel and delegating library work to others are not the kind of responsibilities that drew me to librarianship.

I don't know what your definition of personal achievement is, but I consider each day that my abilities are challenged to help someone a personal achievement. I find exciting and challenging each time I find the answer to a question it never occurred to me to ask & on a topic of which I know little. Every time I find the right book that makes a kid excited to read or inspires in them the desire to learn. I feel like I have acoomplished something whenever I teach someone who is a computer illiterate how to use a computer and use it write papers, job resumes and do research on the internet using reputable and reliable sources. I love to learn and I find great personal satisfaction in promoting that same love in others and assisting them in discovering more about the world that interests them. This may not result in much in the way of financial reward, but for me, it is very rewarding.

If that measure of personal achievement is insufficient for you, than I can just say that it is good that you did not become a librarian.