How can you prevent "scary" dreams

I don't know if emotions are tied to what you dream about or what, but both of my dreams last night were "scary". In a way they were more boring than scary, and how do you change something like, when you dream and outside its night time? How can you change it to day time? Because when its night time in dreams its really, really boring. I'm not afraid of the dark, there's just nothing to do in night time dreams. And also, how can you make your dreams more exciting?

Controling them? Either that or know your dreams will be interesting non-scary and in daytime, that should work.