This is the story of my life in previs. The worst thing I've seen done was an entire sequence was prevised without the environment. So once the environment was ready, the team had to go back, reorient and place everything in the scene and get it to somehow match the original previs as much as possible. Imagine prevising a sequence out of nothingness for weeks, getting daily notes going into polish while knowing that it's all going to change when the actual assets are ready. Then the client has the nerve to complain that 'It doesn't feel the same' when the assets are in. Like Oh this idea doesn't work now that there are houses, mountains, etc and not a void of blocks? So something that should have taken a few weeks now takes 2+ months all because the client can't hire a proper art to make concept or make up their mind about where something is going to take place. Like I don't care if the setting changes from a mountain range to a major city, but to tell people to previs in nothingness is just beyond stupid.