When writing a song with a dark tone, sometimes it's gloomy all the way through. But other times, there is a segment somewhere in the middle that is lighter, often with a bittersweet, wistful tone. Even the instrumentation may change wildly for a brief moment. This segment is usually the bridge. After this bridge, the song resumes its usual, dark tone, though in some cases it may get even more intense than before. It's like a musical