I picked a module of my nodejs app which uses MongoDB to pieces until I had no more idea what could be wrong. It should work. There could be nothing wrong. Then I thought: "What if I try to find() from the wrong collection?" Yes. Fucking YES! I've lost about 2 hours of my life because I've written the collection name in singular rather then plural. Just a fucking single character. Just a fucking "s"! Why don't you output an error? Why? Fuck you! Why don't you do that?