There's a saying in Sunday school that the answer to every question is 'Jesus.' I saw this same phenomenon in organic chemistry class, where the answer to everything was 'resonance.' Why is benzene more stable than cyclohexane? Resonance. Why is any molecule shaped the way it is? Resonance is a safe bet.
I'm beginning to see a sort of answer to every question in medical botany class as well: 'tannins.' Tannins are bitter and astringent plant chemicals, and in addition to tanning leather, they will ripen fruit, discourage bacteria, and much more.