Iran actually spends less on their military (as a share of GDP) then their neighbours (and obviously) more than the USA,
They never start wars. They had indigenous democracy not imposed on them by anyone (until the CIA overthrew the democratic government and put in a monarchy) Iran has been invaded by the USSR, Britain, and most recently Iraq. They may make a lot of noise about Israel, but its just posturing. Iran has never participated in any wars with Israel.
When Iran wants to hurt another country, they support their dissidents with money and weapons, they have not gone to war. They support Hezbollah, Assad, and Iraqi Shiites, (and other Shiites) but they are remarkable peaceful in a dangerous neighbourhood.
Their nuclear enrichment program was very suspect, but its likely to go the way of Taiwans, Swedens, Argentina's or Iraq's, not: Pakistan or DPRK