Two things first come to my mind. The first one is whenever I watch a scene that's in public and there are cars driving down the street far away (Obviously not extra's). I always wonder what they did that day, that week, or how their life turned out? Like in 'Halloween' when Laurie is walking to school or when Annie and Laurie are in the car on the way to babysit and stop to talk to Annie's dad. I wonder if those people know that there in one of the greatest horror/slasher films of all time?

Would they even know it's their car? Would you be able to notice?

My second reason is more horror centered, whenever a character gets stabbed or impaled with a knife/sword etc. How come the blade is NEVER completely covered in blood? Rarely the blade is clean but most of the time there is only a smear of blood, never the realistic amount.