For me its the Ecchi, its poorly executedI'm finding the tone of this manga weirdly off-putting. I can't put my finger on why.
I will point out that the description says he's a second-year middle-schooler. If he acts immature at times, well, that's because he is. I'm hoping there's a long-term growth plan in place (given the apparent longevity of the title, i can't imagine it would have survived without one).This is really going to be hard to read if he doesn't grow up