What makes for an effectively scary horror movie?

Great video essay on the state of contemporary horror and Hollywood:

I am watching Night of the Lepus.

My deepest condolences.

That is a sad attempt at movie making.

The movie that does not contain a fictional ghost feels more realistic and horror

Brexit, Trump, and now Le Pen...

Which do you guys think is the worst horror movie?

Here's a random shotgun blast incredibly terrible, incompetent, shitetastic horror films:
Alone in the Dark (2005)
Manos: The Hands of Fate (1966)
Supernova (I) (2000)
Plan 9 from Outer Space (1959)
Troll 2 (1990)
Sharknado (2013 TV Movie)
Birdemic: Shock and Terror (2010)
The Wicker Man (2006)

Don't forget the two headed transplant films.

The Incredible 2-Headed Transplant (1971) was an atrocity against cinema as well as humanity.

Glad i dint see them! suggest me some good horrors then please.

A kind of arbitrary list of great horror films:
Alien (1979)
The Descent (2005)
Rosemary's Baby (1968)
Perfect Blue (1997): Japanese language
The Others (2001)
The Shining (1980)
Angel Heart (1987)
The Cabin in the Woods (2012)
Let the Right One In (2008): Swedish language
Invasion of the Body Snatchers (1978)
Wicker Man (1973)
The Thing (1982)
The Fly (1986)
Jacob's Ladder (I) (1990)
Audition (1999): Japanese language

POLICE PROCEDURALS/THRILLER:
Insomnia (1997): Norwegian and Swedish languages
I Saw the Devil (2010): Korean language

FAMILY FRIENDLY:
Frankenweenie (2012)
Paranorman (2012)

Seriously? No The Exorcist?

Nope. I'm not a fan.... More laughable than scary. And that list was a random list, not my personal favorite horror movies of all time.

Watched this today. Really effectively terrifying!

I've been watching Penny Dreadful. Halfway through the 2nd season.

Really really good.