Why can't you pull two telephone directories appart that have been paged into eachother?

Ok, so there's this myth that if you set two telephone directories next to each other and then start paging them into eachother one page at a time so that you have the two spines facing the opposite way, you won't be able to separate the two directories by pulling on the two spines. I saw this myth confirmed on myth busters and tried it for myself and it was totally impossible to pull the two phone directories appart, why is this?Why can't you pull two telephone directories appart that have been paged into eachother?
Something to do with the weight of the paper pressing down on the pages?Why can't you pull two telephone directories appart that have been paged into eachother?
It probably has to do with some kind of molecular cohesion, the pages in close proximity are basically attracted to one another, sorta like spaghetti sauce becomes part of the plate if you leave it overnight. Once they are paged together, they effectively become a single unit. Whether that's electrical, magnetic, nuclear, or voodoo, I have no idea, but that's what it seems like to me.Why can't you pull two telephone directories appart that have been paged into eachother?
It is the friction between the pages of the two different books, There is an unbelievable amount of surface area contact between the two books which makes them difficult to pull apart.