Recursion HALP

Hey /prog/, I must say my understanding of recursion is shit (never really dealt with recursion in all my days of writing bad code). How should I go about thinking about it?

inb4 flaming: I understand the recursive concept in some contexts, such as when it is used in a factorial function, but when it starts getting more ambiguous (say, exercise 5, ch. 2 from ANSI Common Lisp) it's ugly.

inb4 RECURSE MY ANUS

>>15
And more to the point your fucking stupid shit nigger. When you have something like....

(fact 5) ==> (* 5 (fact 4)) ==> (* 5 (* 4 ...))

At what point and time do you evaluate fact to a value? At what point and time do you multiply 5 * 4 *...? Your shit diagram doesn't really answer these questions.