I've discovered a way to indicate my mood with a single Unicode character. It's good because it's vague (read: exclusivist (read: élitist)), but as unambiguous as possible (in the circumstances — moods are pretty ambiguous at the best of times).
☰ U+2630 - Trigram for Heaven
☱ U+2631 - Trigram for Lake
☲ U+2632 - Trigram for Fire
☳ U+2633 - Trigram for Thunder
☴ U+2634 - Trigram for Wind
☵ U+2635 - Trigram for Water
☶ U+2636 - Trigram for Mountain
☷ U+2637 - Trigram for Earth
Right now I'm feeling pretty ☵.