So, amung the numerous problems with commercials that have been mentioned (endless loops, not loading, not returning to the content, ect.) I have not seen a mention of an issue I have regularly: commercials cutting in not during a commercial break. I've had this happen several times in the middle of a scene and once literally 5 seconds into a show after the opening round of commercials.
I imagine there is a system that determines and places in the commercials that is in serious need of attention. I doubt your advertisers would be pleased with the bungling of their ads and it is obviously hugely determental to the viewing experience.