My sister said these Sisterhood novels, about friendship of four teenage girls aided by a magical pair of pants, always have this gloomy aura lurking beneath. I tend to agree with her. The word I think describes the series is 'bittersweet', because that's what life is. The four girls, Carmen, Bridget, Lena and Tibby deal with a lot during their teens, and there were always valuable lessons to learn. For them, and also for the readers."The lesson was: Don't open, don't climb, don't reach, and you will not fall. But it was the wrong lesson! She had learned the wrong lesson!
The real lesson... was the opposite: Try, reach, want, and you may fall. But even if you do, you might be okay anyway.
Flexing her feet under the covers, Tibby thought of a corollary to this lesson: If you don't try, you save nothing, because you might as well be dead."