The show is packed full with character driven humour. It comes in both the high and low energy variety. On the whole it's rather loud though. If you're looking for something low-key or soothing, look further.
The fact the show is entirely character driven highlights both its strengths and weaknesses. The characters are, obviously, the most important part of the show. And they're entertaining, original, likable and well-designed and animated. And all of them together make a nice quilt of quirkiness.
But the individual characters are also quite two-dimensional, in the widest sense of the word. Most are endowed with only one or two (very obvious) character traits, which are milked for comedy. But being rather shallow, they run dry too quickly. The show tries to remedy this with a steady stream of new characters. This is especially prevalent in the first two seasons, where there's next to no story progression.
Though there are plenty of witty moments, the space in between is filled with, well, filler; repetitive gags that keep milking the same cows (Taneshima is short, Inami is scared of men, etc.). There are a lot of different cows, which mitigates some of the damage. In itself this would be quite forgivable; many sitcoms are guilty of the same thing, using the same set-up over and over again, and still manage to be amusing. And an argument can be made for repetition being an essential comedic device. But the amount of ingenuity is spread rather thinly over the iterations, there's little variation in the execution. Combine this with the fact there's little to no plot progression and the show can get a tad repetitive, even tedious at times. Especially when you watch more than one episode at a time. So my advice: enjoy, but watch in moderation. Just to make clear I'm not trying to paint a negative picture here, I'll reaffirm; even if you take out all the filler fluff, there is still plenty left to make you smile or even laugh.
As stated before, there is almost no story. Not in the show as a whole and the average episode won't have much of a plot either, just a premise. But it's not about the story anyway; it's about the characters going about their (un)usual business. So I don't think it needed more story, though I do feel it would have benefited from a faster pacing. And in the 3rd season and concluding special, the show finally picks up that pace, finally resolving the few story lines it has. And it does so in style. Its own style, that is.
As a little (but appreciated) bonus: an enjoyable intro clip. It doesn't just rehash existing footage (so lazy) and its quirkiness fits the rest of the show. Panpanpanpan! (See season 2 for this to make sense.)
P.S. Don't forget to check if there's a little extra scene after the credit roll.
