Sakura Kinomoto never imagined that by opening a book in her father's library, she'd be responsible for releasing wild magic into the world, yet that's exactly what she did. Too powerful to be let loose, the magical Clow Cards were sealed away long ago by their creator, Clow Reed. But all is not lost! For the guardian beast, Keroberos, was sealed along with the cards. Can Sakura, with the help of Keroberos, retrieve the cards before they wreak havoc on the town?
Meet Yotsuba Koiwai, the strangest little girl around. With a mind so straight it's twisted, Yotsuba takes everything in life at face value and sees everything with the eyes of impenetrable innocence. With her laid-back father, Yotsuba moves into a new house and makes new friends - friends whose minds boggle at the wacky and somewhat wise way that Yotsuba lives her daily life!
Okay, I'll admit that these don't have much in common on the surface and don't even share a genre. But, if you like manga that makes you happy, both of these fit the bill.
Yotsuba&! is a slice-of-life comedy that follows a five-year old girl as she discoveries the everyday wonders of the world. Cardcaptor Sakura is a magical girl classic by CLAMP.
However, both manga have young female leads who are overall optimistic and love life. Both manga have an excellent supporting cast of friends and family. And both are sure to cheer you up if you've had a bad day.