Thanks! I look at a LOT of horror material, and it seems to me that Teasers cause players to draw conclusions, and their ideas are scarier than any ideas you could ever have, FNaF is a good demonstration of this, the trailers are generally showing very little, thus, the fanbase theorize and get themselves nice and scared before they even play the game! But I think the mystery of what they will meet is the best scare-tactic.
After all, Man's greatest fear is the fear of the unknown.
Another teaser should be coming very soon...