I got two in one day.
One the normal way while setting up a new to me gooseneck.
After I got lucky and found one at a junkyard, I parked the truck in front of the gooseneck with the tailgate down. Wind blew the un-chocked gooseneck off the blocks I had under the jack and bent the second tailgate. Had to take it apart and do some hammering to get it to operate, but I'm still using it.
Learned about four lessons that day:
1. Make sure the tailgate is down when dropping the trailer.
2. Chock the trailer, even if you are only going to be a minute and the ground is flat.
3. Don't use blocks under the jack
4. There aren't enough cuss words for some situations.