"The oldest and strongest emotion of mankind is fear, and the strongest kind of fear is fear of the unknown." H.P. Lovecraft
Starting a new game, this time The Call of Cthulhu. This is a horror roleplaying game based on the works of HP Lovecraft. Rather than the typical demons and vampires and stuff, the Cthulhu mythos deals with alien entities. Also, people going insane is a staple of Lovecrafts work, and it is reflected in this system by a 'sanity' score that goes down as you see mythos creatures or other shocking events. If you lose too much sanity at once you go temporarily insane, and even lose control of your character for a period of time. Aside from that the player characters tend to spend a pretty good amount of time investigating the strange circumstances, not merely going at the entities guns blazing. The reasons for the entities bothering with humanity tend to relate to humanities inherent flaws, such as being summoned for selfish reasons.