I heard this twice the other day. First one, the rider canceled in hopes that somehow there would be an Uber that was closer. When she pinged me again, I accepted then pulled over and waited a couple minutes in case she canceled again. When I finally arrived she ran to my car and complained that she was going to be late. I just said, "ok." She was about a minute past her 7 minute grace period. No sympathy from me. Second one, a lady pings me at 5:30. Downtown. Gridlock. I show up quickly. After we just about get through the jam, my g maps says 14 minutes. I tell her it will be 15 minutes (always add 1-2 minutes per 15 in gridlock). She insists that her Waze and infinite experience are right so it'll be 19 minutes. Her meeting started at 5:30 so if she gets there much past 6:00, it's not worth going. Yes, my fault. We finally arrive at her destination 15 minutes later...6:00 on the dot. Lesson: if you're a rider, assume a couple minutes for your Uber to arrive and give yourself enough time to get there. We don't have hover cars...yet.