Why would Iran default on international agreements, incur harsh economic sanctions, then provoke the US to war?

It’s true that if they withdraw from the nuclear deal completely, they’ll be able to build atomic bombs. In a couple of years—maybe less. If they intend to go to war, I think they’ve sort of lost the element of surprise.

Why would they do this? What could they hope to gain? And why the heck would they be out there blowing up ships in the Gulf of Oman?

How do you feel about the fact that the harsh economic sanctions against Iran are causing suffering only among the citizenry, not the ruling class?