This is an anime that you have to watch. Especially if you like slice-of-life!
There are a lot of events that can makes you cry, laugh or even angry.
After the first episode you'll be perplexed since this anime go backwards without some kind of warning, but after the first five episodes it will be all clear.
The animation is good but the drawings are quite bad, in my opinion. But you'll don't even bother since its history will capture you, totally.
Anyway it's tragic, just to let you know.