If Ramgopal Varma has the gall to say, "This movie is just an attempt to scare you, not that I believe in the supernatural," then you damn well believe him! This man has it in him. Like he says, "Be afraid. Be very afraid."
And no, it's not really the bhoot that petrifies you. It's Varma's use of everyday props - the sound of water from a faucet, the whirr of the fan in the wee hours, the shadow of a candle's flicker, that weird stuffed toy on the loft, the godawful timing of the call bell - that will freak you out.
By the way, does your apartment have a balcony and a creaky elev....