A few weeks ago, I heard some interesting facts on the problem Israel vs. Palestine in the public international law lecture I'm attending this semester. Fact is : until the 1940's, the area around Jerusalem, including Jerusalem itself, was dominated by the Palestine people, while the Israeli were just a minority. Yet following the mass murders in Europe during the Nazi regime, and forced by some influential beings in the U.S., many, many (and I mean : MANY) jewish people, previously scattered all around the world, began immigrating into Palestine, which culminated in the founding of the state of Israel.
I guess that's a very important thing to recognize : imagine your home county is sort-of "invaded" over years, until you're the minority, and you just can sit and watch, because you have no means of stopping it. Wouldn't that result in "frustration", to say the least? And if this situation does not change over the years, but rather gets worse, wouldn't that result in pure hatred?
And here's a central aspect of the problem : the Israeli build the wall/fence to prevent terrorist attacks. The terrorist attacks occured to get revenge for military assaults on the Palestine people. These assaults again were revenge for previous terrorist attacks, and so on, until you get to the point that it all started with the events that lead to the founding of Israel. However, who can blame them for founding "their" state? They were there for thousands of years, it is their origin. But the same is true for the Palestinians. But by the means that were employed so far, from both sides, they cannot co-exist in peace, and probably never will.
A marriage simply doesn't work when it's arranged from the outside. At least in most cases. And once the beds are separated it's difficult to change that again.