Often attributed to Louis XVIII as "Punctuality is the politeness of kings."
But either way it is something I strive to observe. If I am running late, for any reason, I 'phone the person expecting me and declare myself guilty before the appointed time for the meeting, give an estimated time of my late arrival, apologise and offer to remake another appointment.
I am even (reasonably) happy to accept "between 11 and 12" or similar but when 12 arrives and there has been no contact I start to get angry. Today's "between 11 and 12" is now 10 minutes late, no call, nothing.

He will be getting very short shrift when he eventually turns up.
