Do not watch live action Japanese horror movies at night. You haven't learned from the 50 other times you've done this, and now is no exception. (Though to be honest, I didn't find One Missed Call as scary on second watch, nor the TV series of the same name.)
Specifically, do not watch "Sweet Home" late at night. If you have ever seen the movie "Sweet Home", you will probably know what I'm talking about. It was a 1989 movie that actually had a game released on the same day in Japan (it was an NES game, and it's actually just as creepy). Basically about a group of people who enter and get trapped within a cursed house. A lot of fresco paintings, a lot of people dying and encountering weird creatures in horrific ways.
I made the mistake of rewatching this for the first time in a number of years and now I don't want to sleep. But at least I have the compulsion to write now. If there's anything good about this experience, it feeds into what I write in terms of that genre, even if I'm not quite as...graphic as some Japanese horror films go.
But man, this movie was scarier than I remember. *flinches*
(Though on a random note, if they ever made an anime series for Sweet Home, I would totally watch that!)