A good birthday wish to send to a friend is: "May your day be as happy as your friendship makes me." A funny birthday wish is: "Have an ecstatic anniversary of the date you emerged victoriously from the womb."
Birthday wishes for friends can be sentimental, funny, sarcastic, or inspirational. Sentimental wishes express how much the friendship means to you, such as "You're a gift that came into my life. Every day I enjoy the greatest gift of all - our friendship." Inspirational wishes offer encouragement, such as "My hope for you is happiness and success. You deserve the best."