A:
There has been a lot of reasons put forward like injustices committed by the IDF, religious differences, etc.
In 1967, it was Egypt, Syria and Jordan who were threatening to attack Israel. The reason Israel was threatened at that time is the same basic reason why some Palestinians are battling Israel for the land. These Palestinians do not want a 2-state solution from the outset of these talks. They want Israel to move out of there and they do not recognize Israel's right to exist. This was the same argument in 1948 when its neighbors also attacked Israel right after the latter's declaration of Independence.
When the 1967 Six Day War came along,
So what do these Palestinians and other Arab nations really want from Israel. They want Israel to give up the whole land. When Israel gave up parts of Gaza in 2005, rocket attacks from the border of Hamas eventually followed. This is one evidence that at the end of the day, some Palestinians cannot accept Israel's right to exist.
They want the Jews to leave that land. So in reality a 2-state solution will eventually not do any good. It's all or nothing in their eyes.
