The context of the following conversation is Riley returned to the store to return the shirt that didn't fit and find a different one.:
Riley says I had some trouble returning the shirt..
The friend responds This was the one you bought at the Gap store?.
Riley responds Yeah, it didn't fit, and I had to get one that did fit..
The friend responds Why did you have trouble returning the shirt?.
Riley responds They had to look up my credit card since I didn't have the receipt..
The friend responds I usually throw my receipts away, but don't throw my garbage away before I might need the receipt again..