This question already has an answer here:
Old story involving a man who acquires an anti-hallucigen and peels one drug-induced illusion after another from his world:
- New cars become old cars, then clunkers, and finally people pretending to drive cars while running down the street
- Fancy restaurants become dirty dives before dissolving into places where food is dispensed through feeding tubes.
I think it may be by P.K. Dick—it reminds me of his short story Faith of Our Fathers (1967).