I was tied to my twin sister for a day (or the rarely-discussed challenges and benefits of being a twin)

Usually, I don't consider this a disadvantage or a negative in any sense. It's nice, having someone next to me always who understands the way that I think and knows (most of) my deepest fears and the thoughts that I don't really verbalize. But on that field trip, where our invisible connection was materialized, it became clearer and clearer that us-against-the-world could be lonely.