Why did Gandhari curse Shakuni in the Mahabharata?

Why did Gandhari curse Shakuni in the Mahabharata? A curse was given by Gandhari, princess of Kandhar (Afghanistan) to her brother, Shakuni (the then ruler of Afghanistan) that because of your crooked and cunning ways, I lost my 100 children. She cursed him that never ever in your kingdom will there be peace, prosperity and progress. Well ….. How true Hindu scriptures are! Afghanistan in Vedic period was known as ‘Avgan Sthan’ (a defective place).