When you're chewing on life's gristle  Don't grumble, give a whistle  And this'll help things turn out for the best...  And...always look on the bright side of life...  Always look on the light side of life. - Eric Idle, Monty Python

When you’re chewing on life’s gristle
Don’t grumble, give a whistle
And this’ll help things turn out for the best…
And…always look on the bright side of life…
Always look on the light side of life.

– Eric Idle

Monty Python’s Life of Brian