Iran: they are Muslims. They abuse women and are willing to strap suicide bombs on children. They hate more than they love their own children. They are evil.
The devil is always at work.
Iran wants to use nuclear bombs and missile delivery systems to harm Israel so it can then intimidate its Muslim neighbors, with the exception of Pakistan (and maybe Pakistan a little).
Iran want to regain its Persian roots and status in the Middle East. They view their history as entitling them to be a world superpower. North Korea is disparate for hard currency, they would do the devil's work for hard Iranian oil-cash.