It's kind of hard to feel so low, when you're so high. Pink Floyd's music is psychedelic, written to a generation of people who were experimenting with psychedelic drugs, LSD, Psilocybin. etc. If you think that Pink Floyd's music is depressing, it's because you're missing a very important aspect of the music, the psychedelics. Incidentally, psychedelics and Pink Floyd may be the cure to depression.