Introducing the manga that seems ordinary, but it never is. You are brought to a world of a typical calm atmosphere of a high school, with children walking to school getting ready to start class. However, you will be joining a robot, extremely young scientist, talking cat, group of three girls, an irresponsible teacher, and more along the way.
Nichijo is great for the way the atmosphere starts in every scene. By the author giving a scene of normalcy, the reader perceives it as a normal day at a normal school. However, that is when the joke comes in. Usually it is something unexpected, and throws the reader off so much, they just can't help but laugh at the silly situations being portrayed in front of them. That is one of the reasons why Nichijo is so good.
The characters presented in the story each have their own unique personality, and are not cookie cutter(meaning they are not a generic personality that could easily be taken from another source). You have a quiet girl, that usually never seems to want to express using her voice. However, she uses the objects around her and movements to portray jokes and make the reader laugh, and sometimes the other characters as well. Another character is a cat who can talk with a simple generic scarf "crafted" for him so he can communicate to his caregivers. However, he rather portrays an adult mainly, and tries to teach the caregivers the right responsible way of doing things. However, he falls short when he sees a cat toy, and reverts back to "playful kitty mode".
The artwork is nice, however, it is nothing special. It does help though that it is not great, because this series demands a simplistic art style at times. This is not a comedy that shows a sort of 'raunchy' comedy or a 'satire'. Rather, it is comedy that can be enjoyed by many, and has a great amount of variety. Having a really detailed art style might confuse the reader with certain aspects, such as keeping a 'normalcy' atmosphere with the series.
As stated before, the variety of comedy is incredible. you have slap-stick, word bender, romantic, spontaneous, role switch, generic tsun, etc. There is definitely more that I haven't mentioned, I just can't remember every type, and rather I can't also NAME every type that is available.
If you haven't checked this out, I definitely recommend it. If you have any trouble understanding the comedy, try watching the anime adaptation, and then coming back to the series, it really helps a lot.