Actually I think it's about discovering stuff he wish he hadn't discovered on psychedelic drugs.
That's why he wants his mind erased and it also explains the lines about understanding is cruel and ignorance being bliss.
This is also why he wants the fun police to leave him alone coz he's probs doing acid and he knows he's probably screwing his head up but he doesnt care hence "Give me the reason why the minds a terrible thing to waste?".
Actually I think it's about discovering stuff he wish he hadn't discovered on psychedelic drugs. That's why he wants his mind erased and it also explains the lines about understanding is cruel and ignorance being bliss. This is also why he wants the fun police to leave him alone coz he's probs doing acid and he knows he's probably screwing his head up but he doesnt care hence "Give me the reason why the minds a terrible thing to waste?".