See Filmdrunk
Underwater Sorrow is mostly an indie film phenomenon, that I think I may have noticed first in the trailer for Philip Seymour Hoffman’s Jack Goes Boating. “Acoustic music plays and someone goes underwater for some reason†is one of the most pervasive indie movie tropes. I think it happens so often because it taps directly into the mindset of the indie filmmaker: being rich enough to have a pool, yet still being sad.
http://youtu.be/dgHks0Kjd-w