Although a peaceful nation for hundreds of years, Iran was invaded and occupied by the Allies in both World War One and Two. Then in 1980, at the urging of the United States, Saddam Hussein invaded them and used poison gas against both Kurds and Iran. Over 500,000 civilians, Iranian and Iraqi soldiers died in the longest war of the 20th century, which lasted until 1988.
Iran wants war because they believe they can withstand an Israel and US air assault and that unless they are invaded and occupied they can claim victory. No Middle East nation has ever been victorious against either the US or Israel and to declare victory against both will make Iran the leading nation across the entire region, at least for the people in the street. An Israel/US assault would also solve growing domestic political problems against the regime.
Bibi Netanyahu obviously believes Iran threatens the survival of Israel, as no major domestic political reasons to go to war are evident. The majority of Israel's population appears to be opposed to a military strike against Iranian nuclear facilities because of retaliation from Iran and Hezbollah. But as in the US, what the majority of the people want is of no consequence.