Azumanga Daioh is a classic comedy/slice of life series, and deserves all the fame it has. The manga is mostly composed of short 4-koma gags, and the format works really well.

Unfortunately, not every joke translates well from Japanese, so some are a miss, but there's a lot of good jokes that work and a couple visual jokes to compensate that. Some things *maybe* didn't age that well nowadays, but still, a really good manga.