Answer:
Terrorism by Hamas extremists
Rejection of Israel's right to exist as a Jewish state
Israeli settlements in Palestine.
Explanation:
A majority of people in both Israel and Palestine favour a two-state solution to the conflict, but extremist elements on both sides are preventing it.
There are many areas of disagreement, here are three important ones.
1. Terrorism
Extremist Palestinian elements act violently against Israel. Israel responds in a never-ending cycle of Palestinian terrorist attacks and Israeli reprisals.
2. Right of existence
Extremist Palestinian elements deny Israel's right to exist. Israel is fighting to remain not only a state but a Jewish state.
3. Israeli settlements
Israel has created Jewish settlements in East Jerusalem and in the Golan Heights, both of which it has effectively annexed. However, the Palestinians and the international community consider these to be illegal under international law.