and, according to Johan Huizinga
, "an absolutely primary category of life, familiar to everybody at a glance right down to the animal level." Fun may be encountered in many human activities during work, social functions, recreation
and play, and even seemingly mundane activities of daily living. The distinction between enjoyment and fun is difficult to articulate but real, fun being a more spontaneous, playful, or active event.
Creative ideas flourish best in a shop which preserves some spirit of fun. Nobody is in business for fun, but that does not mean there cannot be fun in business. 
Fun without sell gets nowhere, but sell without fun tends to become obnoxious.
Live and work but do not forget to play, to have fun in life and really enjoy it.
People rarely succeed unless they have fun in what they are doing.
It's kind of fun to do the impossible.
Don't ever become a pessimist ... a pessimist is correct oftener than an optimist, but an optimist has more fun, and neither can stop the march of events.
If it's not fun, you're not doing it right.
The wit makes fun of other persons; the satirist makes fun of the world; the humorist makes fun of himself, but in so doing, he identifies himself with people — that is, people everywhere, not for the purpose of taking them apart, but simply revealing their true nature.