Wedding Party on the Lake

Two “why” questions here as I watch this vid.

1. Why did the dock behave so nasty in a moment like this? Video-bombing - literally?

2. Why do people cry out “Oh My God” in such moments? I mean if the dock went the other way – say started flying up with the part on it, would it be “Oh Your God” then?

I hope the dresses weren’t rented though.