Why did union general McClellan take the chance to win the war? What did his hesitation cost him?

Explanation:

McClellan believed engaging the enemy near Washington would yield little, if any, long-term benefit, even with a victory. It would neither win the war nor destroy the main Confederate army, which could simply fall back when pressed by Union forces.This can be both good and bad.

However, more often than not, hesitation can be linked to negative outcomes, since the feeling itself is associated with things such as fear, lack of confidence or overthinking

i dont have that book