The speaker is surrounded by people they can't quite figure out. Their behavior and words seem so strange that it's as if they "fell from the 9th cloud" and landed on their heads. Yet these same people have a huge effect on the speaker's feelings: they bring sadness and happiness, share tears and laughter, and sometimes simply leave. The hardest part is the imbalance. Others seem to do just fine without the speaker, while the speaker is miserable without them.
Even so, the speaker keeps trying to understand, and asks "Why?" The answer comes as two "statements for today." First, nobody can be fully understood, whether loved or hated, because people are complicated. Then comes a twist: the speaker is the most complicated of all. The mood is wistful but wry, with a little humor and a lot of honesty. The final line turns the frustration back on the speaker, which makes the poem feel gentle and self-aware rather than bitter.