Pack up your troubles in your old kit bag
And smile, smile, smile.
Don't let your joy and laughter hear the snag
Smile boys, that's the style
What's the use of worrying
It never was worth while
So, pack up your troubles in your old kit bag
And smile, smile, smile.

(Musical Interlude)

Pack up your troubles in your old kit bag
And smile, smile, smile.
Just pucker up and whistle (Whistle)
(Whistling)
What's the use of worrying
It never was worth while
So, pack up your troubles in your old kit bag
And smile, smile, smile.

(N.B. This is Spike Jones' version. In other versions I've heard,
the third line is:
"while you've a Lucifer to light your f__"

See also:
JustSomeLyrics
111
111.17
Кукрыниксы Это не беда Lyrics
La Peluca de Mirtha La botella Lyrics