We are in the early stages of moving and it got me thinking about past moves. One buyer we had booked her removal van on an hourly basis. Long before money had reached us she was outside demanding to be let in. Her buyers money had reached her but we were still loading vans and hadn't completed on our sale. She got angrier and angrier due to the rising van cost and ended up filling garden with her goods as we moved ours out in time for completion.
We had a good relationship until moving day which was a shame.
I am pretty sure there are much worse stories though.