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."