I write a lot about how Japanese is a vague, nuanced language that can create some challenges for Westerners trying to learn it. Subjects are usually left off of sentences, and passive voice is used more than in English, especially in formal business settings since “it has been decided” sounds better than “my boss decided this, it’s all his fault.” J-List’s manga and artbook guy Yasu summed it up by saying, “We like the grey zone.” The Japanese are fond of euphemisms, too, like seiri (“biology”) for a girl’s menstrual cycle or ecchi (the letter H, pronounced with a Japanese accent) for anything related to sex. There are four demonstrative pronouns in English (this, that, these, those), but three in Japanese, which are kore (koh-reh, meaning this, near me), sore (soh-reh, meaning that, near you), and are (ah-reh, or “that over there, far from both you and me”). The word are also functions as a stand-in for any word you can’t remember or don’t want to specifically mention. Thus it’s not difficult to hear conversations like, “Do you remember that thing? Oh yes, I remember it well. Who could forget it?” with the thing in question never being overtly stated.
Japanese can have conversations without specifying subjects.