Sai's underlining personality is someone who is kind and wishes to create meaningful relationships with others. The problem is, Sai does not really understand emotions, nor even the emotions he himself experiences, hence why he questions others on them and tries to learn as much from he can from books. Sai also tries to pursue friendships, but the concept is very foreign to him, so he struggles with interacting to make those relationships. Still, his friends he has acquired understand his underlying desire to be friendly, so they usually ignore his other personality defects.