The context of the following conversation is Lee came to pick Quinn up but found out that Quinn had gotten another ride home.:
Lee says I am so mad I drove all the way to Quinn's job for nothing!.
The friend responds Why was it for nothing?.
Lee responds Because by the time I had gotten there Quinn had already gotten another ride home..
The friend responds Did she not tell you she had another ride planned?.
Lee responds No, she said that she forgot that I was already on the way..
The friend responds That must have been very inconveniencing, I'm so sorry to hear that..