Most people fail to understand just how intrinsically complicated rides are, and how quickly rides can fault. A lot of ride faults are not even barely observable, for instance I one had it at Ripsaw that at Hideout (final drop) I noticed the movement of the boat seemed slightly off, and indeed, when I went to the control booth later on, the ride had been faulting, something people on the ride most likely would never have noticed.
Another thing to be mindful off, is that whenever there are too many ride faults which require an e-stop (or station stop or ride stop), it can trip up the ride, even cause short-circuiting.