Thomas lend me this great book: Pragmatic Programmer
...at least great until the 40th page since that the page where I stopped reading yesterday ;-)
Funny, easy to read, full of good advises and tips (some I knew, some I didn't).
Now I know I'm not the only sick person who keeps asking "why I'm doing this or that" when I work... :p
They emphasis you to always think about what your doing and why, to see if you could improve the thing (code, documentation, meeting, whatever...) your currently working at and become better.