How is “fun and games” used?

In Dear Zachary: A Letter to a Son About His Father (2008), one line is: “It wasn't always fun and games.”

Which movie is “fun and games” from?

The clip at the top of this page is from Dear Zachary: A Letter to a Son About His Father (2008).

It wasn't always fun and games.

8 作品で登場 · 1 本目

activities that are not serious and that other people may disapprove of

くだけた · 8 本の映画に登場

オックスフォード映画の 100%
activities that are not serious and that other people may disapprove of
Right. Fun and games all the way, chief.
So, after I got shot down twice over Korea, I decided it was time for some fun and games.

定義：Oxford Advanced Learner's Dictionary 第 9 版