Isshuukan Friends.

The relationships are a bit different - parental figure and a young child in Usagi Drop, normal teenage boy and a girl with a special condition in Isshuukan Friends - but both shows excel in one major aspect - the growth, development, and feelings of a small cast of characters. Relationships are a complicated thing, especially when they're just beginning, and boths shows deal with that idea wonderfully. They're light and fluffy in both animation and atmosphere, very fullfilling, and overall just heartwarming. Both shows are an easy, relaxing watch and fans of one will most certainly want to check out the other.

If like feel good anime that will leave you with a smile on your face after each episode then try Usagi Drop and Isshuukan Friends. These are both titles about male/female relationships that aren't romance. In Usagi it's a father/daughter relationship and in Friends it's a budding friendship. In both shows the male lead starts off clueless about his new role, but throughout the series they grown and learn to become better people as they grow closer to the female lead.

While the nature of the relationship between the leads might be different both these show approach their subject matter in the same senstive manner that doesn't shy away from the drama, but doesn't turn it into melodrama either. Instead, both of these shows focus more on the sweet emotions and the drama is always resolved in a way that leaves the characters closer than they were before. 

Even the artstyles of these shows are very similar with soft pastel color palette and cute artstyles that leave the character looking like they are almost always blushing. The charming artstyles of both shows just heightens the good feelings that each episode will leave you with. 

If you want a cute, sweet anime that has enough substance to prevent it from being mere fluff then try either of these titles. You won't regret it.  

Isshuukan Friends has a bit more high school drama and Usagi Drop is more of a parental relatioship but both animes give off a heartwarming feeling and keeps the smile on your face.

If you like Kayo x Sotaro, you might like Isshuukan Friends. Both heroines are pretty similar where they are lonely and protagonist is trying to be their friends.

It has the same storyline, about a girl who doesn't make friends and a boy who wants to be her friend. It's very touching.

Isshuukan friends and Suki-tte Iinayo both tell gentle stories of a boy who helps a girl overcome her shyness around other people. If you like a cute story about a developing relationship, full of soft emotion, check both of these out!