It was a two state solution, but from 1948 on their have been terrorist attacks from each other trying to drive each other from the land. Meanwhile there has been a worldwide emigration to Israel of Jews from around the world and they outnumber Palestinians 4:1 to it is unreasonable to assume they should have the same amount of land. Israel has also turned many areas that were uninhabited into a garden (Negev Desert) so there is that as well.
They did seize the Golan Heights but that was after Syria tried to wipe them out using the heights to shoot down on them from. They seized this not just for self defence but because 30% of their watershed is based on control of those heights and to protect their water supply they need that. National boundaries are supposed to make sense, giving an enemy that tried to wipe you out control of your water supply does not make sense.
I couldn't disagree with any of this, even if I wanted to... which I don't.
But can you, for a moment, try to think of the Palestinian perspective?
They were promised a nation for helping in the overthrow of the Ottomans.
They were denied the promise in favor of growing sentiment for a nation for Israel... prompted in large part to "Darbyism".
Further treated poorly by Zionists to the point that they battled both Zionists and the British.
Further mistreated when Israel defied the UN's plan by taking more land than was allocated by force, and forcibly removing the Palestinians.
And ever since 1948 Israel continues to take more land... most through winning battles against it... and they've pushed the Palestinians into the West Bank, Golan Heights, and Gaza.