You won't want to read my stories! mwahhhh hhahh haahh hahh
At exchange solicitors have all parties sign copies of contracts undated, both solicitors speak to each other on the morning of completion to confirm no problems, the solicitors date the already-signed contracts and the deed is done.
Except....
A friend of mine was part moved in to his new house when his stricken solicitor phoned him to announce that, although she had spoken to the vendor's solicitor that morning, the vendor's solicitor had not at that point spoken to the vendor. Who, it had now transpired, had died in the night.
Since they were already partly in, and had handed over the keys on the house they had vacated, my friends were able to agree with the bereaved family that they would rent the house from the estate while it all got sorted out. But there was no will, so it all took ages, and my friends ended up renting it for 12 months before they got title. (Which meant no alterations for 12 months, which was a real nuisance.)
I think the rules were changed after this, and both solicitors do now have to speak in person to their clients before completion is effected.