For many years now, Israelis and Palestinians have lived in each other one's pockets, shopped in each other one's cities and managed to annoy each other to no end. Each time the Peace negotiations would approach some point at which the solution could be within grasp, one side or the other managed to derail them. The Palestinians managed to derail negotiations more often due to their deep internal divisions. So for example, if the PLO was close to reach an agreement with Israel, Hamas felt it was time for a suicide terrorist attack or time to kidnap a soldier to make sure the Israelis got pissed off and refuse to keep talking; or maybe the Israeli society would feel that the attacks represented a security risk which needed to be addressed before any agreement, therefore stopping the agreement.
If Hamas showed any kind of flexibility toward Israel (granted, that is very rare), then the PLO would increase their demands to extract more concessions from Israel, and Israel – feeling blackmailed – would back off.
If the Israeli government inched close to a deal with the Palestinian Authority, then the settlers' movement and their supporters would torpedo it. How? If the government included some of their supporters, by destabilizing the government; if it didn't – then by creating new realities on the ground or announcing expansion of settlements at the worst possible moment.
The examples could go on and on, but as I hope I made it clear already it boils down to different actors on both sides of the green line knowing when to throw the wrench in the works to stop the process. Arafat was a master of derailing negotiations, and one of the reasons Hamas insists on the dismissal of Salam Fayyad is because he gets along relatively well with his Israeli counterparts.
It becomes apparent that for some groups, the Peace process is not about reaching an understanding but about establishing positions to continue the fight, and apparently these groups believe that anything short of 100 % of their demands is unacceptable. Of course, the worst of it is that they force the moderates into untenable positions and make it impossible for them to negotiate. The net result is the dead of dialogue and the rise of posturing...not exactly the climate you want to reach Peace.
It is the intimate enmeshment of the lives of Israelis and Palestinians that makes “pushing the buttons” so easy. Salam Fayyad understood it when he focused on building a separate economy and social institutions that could stand independently from the Israelis, and successive Israeli governments understood it when they moved ahead with separating...whether it was the separation fence or the Gaza disengagement.
Sometimes in a marriage, husband and wife argue so much and hurt each other so much that the healthiest course of action is a separation or a divorce...the same can be said about Israelis and Palestinians. Rabin saw it in 1993; Netanyahu sees it in 2011. Separating makes it more difficult to push each other...