I've been on Gringotts a couple times when it glitched/E-stopped. The first time I ever went on, the sound effects weren't working. All the normal audio worked except sound effects like the dragon roar. Another time, the ride stopped, then continued to the next scene, then stopped again. It was pretty amazing to see how the ride worked. I also thought it was neat to see the "squinching" effect used in the Bellatrix/Voldemort first encounter scene. And it was a bit scary when it started randomly spinning while the vehicle was stopped, haha.
PS: I've also been on Spider Man when the audio at the end of the ride started playing at the beginning of it. The disco/upbeat music definelty added a different feeling to the ride.