Do ghosts really exist? Of-course not! I think that people are absurd to believe that they do. These people have dillusioned themselves into believing that they do exist and further more, let these imaginations conjure up things that are not there.
Many people have narrated incidents that they believe have occurred to them but without proof, who can really know if they are speaking the truth. As for haunted houses, this is a way of peoples story-telling abilities to come out. They wait for these opportunities so they can say all sorts of things. You could tell a person that, that house has been vacant for years but wouldn't it be more spontaneous if you told them it was haunted? You make up a legend pertaining to the house, which you know, is not true.
As for critics, who believe that these strange things happen are due to ghosts, they are wrong. It is the doings of polthageists (Jinn's). The Quraan, in numerous verses has proved their existence and many incidents are reported in various Ahadeeth. In the Bible, mention is also made of polthageists. This is the explanation- the only explanation of ghosts.
People concoct people like Santa Clause, goblins, elves and ghosts to satisfy their vivid imaginations and most importantly to justify what are true miracles of Allah! It is mostly people who do not believe in God, that do this. We believe in Allah and know that there are things unseen to us and we believe in the miracles of Allah. The people who don't believe in God crave to satisfy this missing part of their lives by confusing miracles with beliefs that it is merited to the much-fabricated ghosts.
I, for one, do not believe in the existence of ghosts and denounce proof of their existence. I admit that it is fun to make-believe that they do exist but we should know where to draw the line between fictitious and reality and ghosts are definitely not a reality!.