This song just makes me smile. I guess it is probably because my Mom sang it often. I assume that others have songs that they like just because it reminds them of a person or a memory.
The advice in the song is simply to remind you that life is to be enjoyed. You can in almost any given circumstance find some kind of joy. I hope you listen to the song and think of something that makes you happy. This musical interlude is a gift to you.