Whither Sarcasm

"Apologies - there will be no further delays.  My cable technician has neared your home, and will be at your home in precisely 7 minutes" said the clipped military voice from the cable shop.  And typical of a person who values and measures time precisely, he hung up before I could ask him anything else.

I can understand if a person says "5 minutes" or "10 minutes" - it typically means in Egypt (as in India) anywhere from 30 minutes to 4 hours.  But the "7 minutes" had a ring of authenticity to it - nobody can be so precise unless they know for a fact that it is indeed going to happen in 7 minutes.

I waited.  And waited.  Finally he turned up almost an hour later.

After the repair man left, I called up the cable shop owner to give him a piece of my mind.

I (in my most sarcastic tone) : "Your cable guy finally came to my house in PRECISELY 52 minutes 37 seconds after your phone call".

Cable shop owner : "He came, did he?  Good.  Good night" and then he hung-up before I could slip in another word edgewise.

I am losing my faith in sarcasm.