The show is about an excellent and popular schoolgirl who behaves completely different when she returns home. She turns into a spoiled brat who does nothing but playing games, reading manga or watching anime. Her brother lives with her, despite being older and more responsible, he lets her do whatever she wants and fulfills her demands.
I don't feel there is any story in the show, all episodes follow this pattern: Umaru wants something (a game, magazine, etc) and annoys her brother to buy it for her, her brother refuses and she starts a mess, brother gives up after a while and says "it cannot be helped", so he buys her what she desires and that's the end. The show is centered on Umaru, all the characters and events develop around her and go in her favour, there is no feel of progress or story moving on, just Umaru using others to get what she wants and things go where they were at start of the episode.
Art and sound are the only elements which weren't horrible, but they aren't much good either. Art is basic and nothing special, also sounds and music aren't memorable but not bad.
The show lacks in character customization terribly. The protagonist is displayed as cute, while having nothing but bad traits: arrogance, manipulation, disrespect, childish behaviour, sloth, etc. Other characters are far more likable than her, some of them have quirky characteristics or seem nice people, but in the end no matter what they stand for, they just adapt to protagonist's desires like it doesn't contradict their morals. No matter how many times it seems there may be some progress when characters socialize, in the end Umaru jumps in and ruins the atmosphere, she is the main reason why this show is terrible. Question is why would anyone make a character like that and set it as a protagonist, also put in a show with no story at all...
The only enjoyment I had was when some characters faced each other and there were few funny moments, until Umaru came and turned everything about herself. What is the purpose of the show? The protagonist was nothing but a nuisance which removed every element of comedy. The show would have a point if Umaru changed in the end, to realize her behaviour, but no, her brother and other characters let her use them to get what she wants. It is annoying to see someone making a fuss over a toy, especially when the other person is trying to get some sleep or returned after stressful day at work. It wasn't funny at all, I felt bad for her brother having to deal with her... I hoped he would teach her lessons how to become a responsible person, but no, he is a weak character who talks about responsibilities but lets her get away with anything she does to him.
