Final answer:
The sentence contrasts Sam's realistic and pessimistic point of view with Amir's more optimistic or carefree attitude by their different reactions to a lost wallet.
Step-by-step explanation:
The sentence "Despite being amused by Amir's words, Sam thought his friend unrealistic and knew that his wallet and his twenty dollars were gone forever" demonstrates a difference between Sam's and Amir's point of view by contrasting their reactions to the lost wallet. Sam believes the situation is hopeless, and his money is unrecoverable, showing his pragmatic and perhaps pessimistic outlook. On the other hand, Amir's attitude, which amuses Sam, suggests a more optimistic or carefree perspective, where the loss might not be seen as permanent.