Evan is feeling guilty for taking his sister's money. I think we all have a conscience that let's us know when we are doing something wrong.
I think Evan is regretting taking his sister's money. What the statement means he is reminded of his sister's money and he can't do basketball correctly because the money was on his mind.
Every time Evan moved the envelope reminded him he had done something wrong and he was feeling guilty about taking the money from Jessie.I felt guilty about how I treated my sister some times.
I think that every time the money slaps his leg, it feels like he's being told how he shouldn't have done that to his sister. I feel that way when I know I did something I shouldn't have.
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