For a number of reasons (at perhaps a reduction in security) I tend to
have thumb screw locks on the inside of doors.

Modern doors in particular though what's the crap where you can't unlock
the chuffer if there's a key in the other side?

The doors at work suffer the above, and we are often locked out of one
or other of the doors, depending which way we leave.

Somehow though we've managed to lock the front door last night, despite
having left a key in the inside but couldn't unlock it this morning. And
i'd locked the back door from the inside and left the key in that.

Anyway after much faffing we got in and the lock has been changed for a
thumbscrew.

Apparently it's beyond us to consistently remember to remove the keys!