Recently I play some games, and these games inspire me on treating the player unfriendly. 1. Loots with debuff or foods with side effects In "slay the spire" every relic has a negative attribute, and you have to give up something to receive the benefit of the relic. In "project zomboid" there are foods with side effects. 2. When the player level up, not only give good trait but also bad trait. In "Darkest Dungeon", I think the player has 50% to get a bad trait when leveling up. 3. Random events with bad things. In "rimworld", there are a lot.