as nice as pie
idiom

- if someone is nice as pie, they are friendly to you when you are expecting them not to be

(Cambridge Idioms Dictionary)

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Pie has long been synonymous with the adjectives nice, or pleasant. This usage originated in America and likely stems from the simple association of pie as something especially pleasing. As the Phrase Finder points out, Mark Twain used it frequently in his 1884 book The Adventures of Huckleberry Finn:

"You're always as polite as pie to them."

"So he took him to his own house, and dressed him up clean and nice,... and was just old pie to him, so to speak."

The expression "as nice as pie" is often accompanied by a qualifying statement such as, "I thought he was going to be angry because I was late, but he was as nice as pie." This helps to explain the unexpected pleasantry. The following are other examples of idioms that rely on pie:

- as easy as pie = very easy (The exam was easy as pie)

- as American as apple pie = to be typically American (Cowboy boots are as American as apple pie)

- pie eyed = to be drunk (He was pie eyed by the time he left the pub)

- pie in the sky = a plan that appears to be good, but which is unachievable (His plan to set up a web site to buy and sell used mobile phones was pie in the sky)

- finger in every pie = to be involved in many activities, often to the disapproval of others (If you have your finger in every pie, then don't complain about being too busy)

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SMUGGLE OWAD into today's conversation

"The passport officer at the airport was as nice as pie."