Nothing too drastic, but one was funny in retrospect: First trip with kids a few years ago when they were DD7 and DS10.
I love the Haunted Mansion, didn't realize that both were mildly freaked out. I had DS on my Doom Buggy, DD was with DW.
Just when you reach the point where the buggies turn around and you go backwards down the hill, I heard DD scream as it leaned back. Whoops, forgot to warn the kids!
Then: Stopped, for a long 5 minutes while leaning back. We laugh now, but later in the trip I said, "Hey, let's take another HM ride!" and both kids kinda shook their heads at me. Luckily, 2nd trip they were back on board.