General George McClellan's cautious military strategies during the US Civil War led to increased Union casualties and missed opportunities to end the war sooner.

Explanation: General George McClellan, pictured, was a Union general of the US Civil War. Other than his famously tense relationship with Abraham Lincoln, he is remembered primarily for his ridiculous level of caution in military operations - something which, counterproductively, resulted in a great many more Union deaths than an aggressive approach would have yielded. Several opportunities to shorten or outright end the war were lost because of McClellan’s tendency to overestimate the enemy by a grotesque margin. Nevertheless, he was a good military administrator and organizer, and he did make the Union Army under his command into a formidable fighting force. He just didn’t fucking use it.

Explanation: General George McClellan, pictured, was a Union general of the US Civil War. Other than his famously tense relationship with Abraham Lincoln, he is remembered primarily for his ridiculous level of caution in military operations - something which, counterproductively, resulted in a great many more Union deaths than an aggressive approach would have yielded. Several opportunities to shorten or outright end the war were lost because of McClellan’s tendency to overestimate the enemy by a grotesque margin. Nevertheless, he was a good military administrator and organizer, and he did make the Union Army under his command into a formidable fighting force. He just didn’t fucking use it.