The female lead does push beyond what I like to see in a character in a standard / slice of life manga, particularly with the blackmailing threats and stealing. Possibly a bit too selfish, like Gen mentioned in the first chapter, but we'll see how that part develops. I'm thinking she'll wind up being 18-21 or something since she calls him uncle (as in someone older than her). Some assertiveness is nice, especially with Gen portraying the laid back part, so far.
But the main thing I came here for was that I love the single use coffee filter depicted. Those things are great even for home or hotel use.