Everybody goes to heaven then what is hell for?

As everything I write on my website is my personal opinion and I am not making a judgment on anything, this article although extremely sensitive to most people will be laid out in as fairly as possible based on my knowledge. So here it goes, there are more people affiliated with one religion or the other and everybody thinks or knows that they have a fair idea about where they are going. And the first and the last choice of place to go when you die has been Heaven. Every religion on earth thinks of that place where they will enjoy their eternal life in peace and tranquility with no worries and all luxury and everybody has an idea and they are pretty damn sure that they will end up in heaven. This core belief is so fundamental in every religion that all the religions that their followers will end up in heaven and the other followers will be sent to hell. Even the sects in each religion accuse each other of going to hell and assume that they are the rights to interpret the scripture and thus go to heaven. Now here is my question, if every religion (and various sects within that religion) thinks or are pretty damn sure that they are going to heaven so it leaves out only the non believers going to hell and even that is not the case anymore since recently the Pope has said that non believers can also go to heaven. So everybody thinks they are going to heaven then what is hell for? Because in some religion they say that even if you are really a bad person, GOD in his wisdom will forgive you and let you go to heaven (after some kind of punishment).