Why is chemistry called the central science?
It serves as a bridge between the hard, logical physical sciences (e.g. math and physics) to the soft, conceptual life sciences (e.g. biology and social sciences).
Clearly no specialization of science is "easy" so these terms are relative. You're not a very respected member of the science community without Dr. in front of your name, in most cases. This translates into a decade plus of intense study of science, and anyone who has went to college can relate science is probably the hardest subject area to graduate in, even before graduate school.