I've liked this anime so much. The history is not something very complex, by the way, it is pretty simple. But the anime is so interesting that makes you want to watch more even without a complex history behind. The humor is nice. Particularly I've liked a lot the animation and expressions of the characters, it is "one more point" that made this anime so funny. The characters are so different between each other, and it's nice and funny to see their friendship because of this. They are very cute too! The only thing I didn't like so much was the fact that the episodes are pretty short (sevenminutes each one), the anime is pretty interesting and I wish I could watch more. That's why I'm giving rate nine.
Conclusion: I recommend a lot this anime if you are looking for a simple history and humor.