Chord theory is much like any other facet of music theory because of the nearly endless possibilities that arise just from a single principle. Once you become familiar with basic chord structure, deciphering more complex chords becomes less ominous and foreboding.
Terms such as diminished, suspended, and augmented; along with interval extensions like add9 and C13sus2 look as though some mystic understanding of the universe itself is a prerequisite to understanding chord theory, but after being acquainted with a few simple principles, the theory is much easier to comprehend.