Genre savvy and stressed decisionsOne of the most frustrating things I have encountered, amongst many friends and acquaintances is when watching a film or television, they will berate the characters for not making a particular decision. "Why didn't they just do that?" They'll inquire.
Now this is an easy mistake to make, and it's something I have indulged in, and sometimes it's an accurate criticism. Sometimes characters do act like colossal idiots. But here's the thing: we all act like colossal idiots all the time. We often don't think things through, we rarely make decisions based on all the facts, and if someone was to watch our lives they'd probably make exactly the same criticisms.
Often in these films it will be during points of high stress that characters will make these choices, when they don't have time to think through their actions, and they are not thinking rationally. It's impossible to know what one would do under such a situation until actually being encountered with it, so making sweeping generalisations can be foolish. Added to this is the fact that they don't know they're in a horror film- splitting up is not always a terrible decision, especially if you do not know that there is a dark horror waiting to devour your souls around the corner.
Ultimately I'm usually willing to give characters a break- their acting stupidly isn't always the writers making their lives easier- sometimes its them following through on the characters.