Watashitachi wa Koi wo Shiranai is a simple romantic comedy manga of the 4 koma format. The main concept is of a bit mismatched couple that are a bit dense about their growing mutual crush. Yuki writes web light novels and is very serious, Hayato is kind of an airhead.
This manga is seinen, but mostly reads like a cute, innocent shoujo, save for the large breasted rival, and the occasional mention of porn.
I'd say it's kind of an average manga of its type. The concept isn't inherently funny, unlike the really good 4 koma manga I've read like Tomo-chan is a Girl or
Monthly Girl's Nozaki-kun, and the jokes aren't really the laugh out loud type, and therefore its appeal rests solely on its characters, which at least feel unique rather than bland as is often the case in romance manga. In all, I'd say the manga is cute, but never pushes itself to really shine. However, the art is pretty stand-out for a manga of this type. There was never any questionable anatomy, and everything is very cleanly and confidently rendered.