It is a great mitzvah to be happy always.
Charity with a smile shows the donor's character.
Don't ask God to change the laws of nature for you.
If you are not a better person tomorrow than you are today, what need have you for a tomorrow?
A drunkard cannot plead his case.
Even if you can't sing well, sing. Sing to yourself. Sing in the privacy of your home. But sing.