Cheap and silent, they are the most effective means for the impoverishment of a whole country.
Sanctions mildly weaken the strongest of a society and kill the weakest.
The danger of sanctions is that the application of them is often done without much forethought for the consequences. Sanctions are easy to misrepresent as innocuous, as is the case with the sanctions on Iraq. Obviously, the chance to meet the president of such an association would be a once in a lifetime opportunity.