I love a good thrill. Seriously. When my heart races and palms start to sweat in anticipation of the scare to come, that's one of my favorite feelings. And I'm not alone. Several studies have found that people enjoy any number of frightful things — horror movies, sky diving, roller coasters, and of course, haunted houses — just because they like to be afraid. For example, researches at the University of California and University of Florida in 2007 found that sometimes people experience positive…