Why was McClellan wrong?

George McClellan, the Union general during the early stages of the American Civil War, was often criticized for his overly cautious approach and reluctance to engage Confederate forces decisively. His hesitance to pursue aggressive tactics and capitalize on opportunities, such as during the Battle of Antietam, allowed the Confederates to regroup and prolong the war. Additionally, his failure to leverage the Union's numerical and logistical advantages contributed to missed chances for decisive victories, ultimately leading to his removal from command.