Failure to Practice Basic Home Safety
My basement is bright and open and literally covered with toys. In the movies, however, the lowest levels are always home to crazed psychopaths, dead bodies and torture chambers; so why do people insist on descending those fateful steps upon hearing a strange noise? Because it's a horror movie, that's why.
Movie characters always seem to make the dumbest decisions possible for our viewing pleasure. Why doesn't anyone look through the peephole before answering the door; think twice before picking up a hitchhiker or install a window covering or two. C'mon, fictional characters (and lazy screenwriters), you know your mamas taught you better than to take candy from strangers!