[A] quotation is a handy thing to have about, saving one the trouble of thinking for oneself, always a laborious business.

Milne’s wry remark satirizes the way people deploy quotations as intellectual shortcuts. A quotation can lend borrowed authority, polish, or wit, allowing the speaker to appear thoughtful without doing the harder work of forming and defending an original view. The line also pokes fun at the social habit of “name-dropping” respected writers to win arguments or decorate conversation. At the same time, it acknowledges a truth: independent thinking is effortful and often uncomfortable, so the temptation to outsource judgment to ready-made phrases is strong. The humor lies in the deadpan admission that thinking for oneself is “laborious,” turning a moral critique into a self-aware confession.