I've got rid of the emptiness by reading the books only about RULES... I'm not saying they are useless, what I mean is that Reading Source code and researching algorithms will make you catch the point.
I'd like to say a programmer who's willing to improve his/her internal strengths has to adjust his/her way of learning toward the two : Reading Great Sources & Researching Algorithms. They are the final form for learning.
Of course, doing sth. by yourself can be more benefic.