Folly is an elusive concept that comes in many varieties. Anyone can act foolishly sometimes, but people under the spell of folly act foolishly again and again resulting in actions that end or can end, in disaster. I can do no better than to give you classical examples of folly which may interest you in a military scenario. Modern folk still tend to regard folly fatalistically. How irresistible it is to blame folly on fatalism.
History records the example in the Greek conquest of Tory.
The Trojans were vehemently warned that the wooden horse left behind by the Greeks had soldiers hidden inside. But they did precisely what they were told not to do when they hauled it within the City walls. When can we as individuals learn from the record in order to avert it personally. In modern layman language I would like to share the following points. The Facts - Folly prone people have the habit of twisting facts around to justify what they want to do.