The Oregon Trail took you west
Imperialism hurt European nations by slowing trade and development of new and recent industries.
Americans were unfamiliar with the territories of Vietnam and ended up having to search manually, house by house, allowing the Viet Cong to dig escape tunnels and snipe American soldiers.
For Italy, they were spies who collected top secret knowledge for the Allied Powers. They were U.S. soldiers who fought off the enemy successfully. They were British troops leaving their units to join the enemy.