Fail to keep their word.
I leased a car from Saint John Volkswagen, impressed that the sales guy said it only needed an oil change every 12 months. Then in 6 months I got a call from the dealership looking to book my 6-month oil change. I made a service appoint 9 am, but when I arrived they couldn't get it in until noon. Another time, they booked me in for an all-day appointment but didn't start working in time to finish by supper. I've found this business very unreliable.