Another nice thing about getting old is you can leave any social event early just by saying you’re tired.

George Carlin (1937-2008) American comedian

Show (2008-03-01), It’s Bad for Ya, “Old Fuck,” Wells Fargo Center, Santa Rosa, California (HBO)

(Source (Audio); dialogue verified)

Variant: "One great thing about getting old is that you can get out of all sorts of social obligations just by saying you're tired."