I'm not so great with wallpapers, but this challenge looked like fun so I gave it a go! The first thing that came to mind when I saw it was Ouran Highschool Host Club, everyone's always so happy, and the general overtone is very pink and flowery so that's what I did
Please enjoy

http://gallery.yopriceville.com/var/albums/Flowers-and-Hearts/Pink_background.jpg?m=1399680380
http://1.bp.blogspot.com/-WdM0skIbXq8/UBIqHiGZKtI/AAAAAAAAAEE/bKne42uhzjg/s1600/ouran02.png