YOU SHALL ALL FALL BEFORE THE MIGHT OF C'THULU! Now, you do not believe in his evilness, but ONE DAY! One day, C'thulu shall awaken and devour this world whole! You unbelievers and your science and facts, one day C'Thulu shall rise and you shall weep tears of blood. Maybe then will you believe.
See how bloody retarded that sounded? Now substitute C''thulu with ghosts. Not saying they're fake, simply making it clear that saying "ghosts are real, and you'll see one day *shakes fist*" makes you look foolish.