The Pink Smiley symbolizes "Love".  Someone you love. Let that special person know that you are thinking of them and that they are loved.

The Yellow Smiley symbolizes "Happiness".  Someone who has made you happy, like a friend, a relative, a teacher, or anyone who made you smile.

The Green Grouch Symbolizes "Crabbiness".  Someone that has been mean to you, or hurt you. Or, to apologize if you have been a Grouch

The Blue Smiley symbolizes "Coolness".  Someone you think is really cool, like a friend, a parent, a child, or anyone you think is cool.

The Purple Smiley symbolizes "Respect".  Someone that you look up to or to someone that has done something very special, like passed a class, won an award or did a good job.