Which verb is used incorrectly? The Long Line

After we finished shopping at the grocery store, we stood in a long line to pay for our food. The customer ahead of us bought a tremendous amount of food, so the cashier was taking a very long time to complete the transaction. As we continued to wait, the customer behind us dropped her bag of oranges. So we assist her by picking them up. In the end, we did not mind waiting because we encountered an opportunity to help somebody.