We learn a little something about Jason's home life. What's that, Jason? You've got your mom's mummified head on a shabby chic end table in your living room? We're gonna give you the benefit of the doubt and guess that you weren't expecting guests.
You get freaked out by a false scare (it turns out to be nothing). This is known in movieland as a "cat scare," which is a bit of a misnomer since cats really are trying to kill you.
Somebody gets killed in a refreshingly inventive new way. Sure, a machete works, but Jason likes to mix it up with a pitchfork, wrench, barrel of goo, tree branch, or, I dunno, a guitar.
You see from the killer's point of view. "Stalker vision" is also what I get when I see Taco Bell.
Someone decides -- against all logic and common sense -- to investigate something strange. I don't know about you, but if I were in a cabin in the woods and I heard a scary noise, I wouldn't be like, "Hmm, sounds scary as fuck. Better check it out up close."
Bonus Drinks
Wounded killer! Take a celebratory swig whenever Jason (or, uh, a relative of Jason's) gets hurt. Unless you like to root for the bad guy, in which case take a swig anyway. Jason is basically filled with worms and stuffing, he's fine.
Take a shot of Fireball whisky (or drink of choice) whenever there's an unmasking! I don't know why people are always trying to take off his mask. He looks fucked up WEARING a mask -- you think it's gonna be better underneath that thing?