As one gets older one doesn’t feel quite so strongly any more, one discovers that everything is always going to be exactly the same with different hats on.

Noël Coward (1899–1973) English playwright, actor, wit

Letter (1959)
    (Source)

More frequently paraphrased (as in The Film Daily in 1964): "As one gets older, one discovers everything is going to be exactly the same -- with different hats on."