Lying and Cutting in Line... What For?

On my way back from the Illinois trip, I observed some funny behavior.

When I was at the counter for the rental car return, a young lady walked up from behind me, dropped her paperwork on the counter, and said loudly, "I hate to do this, but I really have to go. My flight leaves in 20 minutes. I am really in a hurry." Ok, so I let her cut in line. Although I wanted to tell her that if her flight would leave in 20 minutes, then the airline would have cut-off the check-in already, which was the exact reason we missed our flight earlier. But I didn't say anything because it was really not my problem.

Unfortunately for her, the rental car agency wouldn't send out a shuttle just for her. So, after I completed my rental car return transaction, I got on the same shuttle, and saw her sitting there still. So, she didn't really buy any extra time by cutting ahead of me.

Once we got to the airport, she headed to the other side of the lobby. Later I saw her walking back towards our direction. It turned out that she was on the same flight as we were. So she totally lied, because our flight wasn't leaving in 20 minutes. It was leaving in an hour. She had no rush at the rental car agency.

She ended up waiting in line at the check-in counter behind us. When the airline agent called for the next in line, she slipped through the line between me and the pole, and went to the employee. I was really aggravated at that time, because she had no reason to cut in line at all.

Sometimes I don't understand why people do certain things. Her lying and cutting in line didn't get her any more ahead than if she would just take her turn. We were just sitting in the waiting area by the gate after we both check-in anyway. It's not like she got to fly sooner or anything. What's the point?