"You'll never know the murderer sitting next to you. It's from the song of Twenty One Pilots "Heathens". This sentence made me to think a lot about the people we know for a long time and if we know them in real. Everyone has sides which they try to conceal and getaway from their real "I". People are trying to play roles, to fit in or satisfy needs of someone or groups. So what can we do, if the people we're interacting don't accept themselves the way they are? How can we know what they are capable of? Maybe we're sitting next to the murderer?"