.flow/theories

Theory 1/example
Based on how Sabitsuki never leaves her room unless she accesses her computer, she may be known as a shut in. some of the NPCs she encouters may be some of the only friends she is able to have or access. Hating reality, she goes onto her computer and tries to escape responsibilities in her life. In the School, she gets chased by the Red Demons, or Kaibutsus, at a certain point. This could mean she was bullied or even harassed. While you see countless demons trying to get her while she is ruing through the hallway, this could mean she is a target in her school. Knowing how Smile never seems to be a nuisance by trying to kill her in anyway, could be a friend to her as well as some of the other NPCs. However, you see Smile the most around the dream world, possibly for support. Another example is how she can get possible revenge on a certain NPC Kaibutsu. How she tries to stand up to him when you select the Pipe effect. When you try to hit it, it automatically turns around and kills Sabi

Another theory i have came up with is that .flow takes place in an apocalyptic world. seeing how it is always a darkish grey green sky when you go upon the balcony. The Human Brain is also not creative enough to imagine another living human being. possibly based how Sabitsuki can go outside on her balcony that is the only possible way for her to see any other human. as for smile and sister, they could possibly be neighbors or someone who she just happened to see all the time, possibly a close friend maybe.