According to Roger Waters, Barrett came into what was to be their last practice session with a new song he had dubbed "Have You Got It Yet?". The song seemed simple enough when he first presented it, but it soon became impossibly difficult to learn and they eventually realised that while they were practising it, Barrett kept changing the arrangement.[79][82] He would then play it again, with the arbitrary changes, and sing "Have you got it yet?". Eventually they realised they never would, and that they were simply bearing the brunt of Barrett's idiosyncratic sense of humour.[83] Waters had called it "a real act of mad genius".[79][82]

Also TIL about Pink Floyd:

Every song from Dark Side of the Moon is about something thing that too much of will make you crazy! Money, Time, etc.