I've been looking at the MO:s of different molecules in Avogadro, fascinated by their magnificent geometries. But how is one supposed to interpret them, so as to understand their reactivity? What are the first interesting things one should note when looking at the MO:s of different molecules? Interesting patterns to recognize? There is a lot of technical information on MO theory but not much info on how to interpret them intuitively. Any other sources or books I should read?