A non-serious but I hope interesting question.
Not for the first time DW and I were recently reflecting, having just had a very enjoyable and mutually satisfying sex session which lasted a maximum of 15 minutes (not that I was timing) that sex doesn't have to last hours and hours with endless amounts of orgasms to be really, really good.
I think we were both grew into young adulthood with the impression that bringing each other to the heights of ecstacy all night long is the ultimate even though after a lot of years together we know that's not necessarily the case - or usually very practical!
That's not to say that occasional lazy, unhurried morning lie-in sex isn't wonderful or that quickies - a rarity these days - aren't fun, and indulging in extended foreplay from time to time isn't very, very pleasant. But, at least in our experience, some of the best sex can last 10-20 minutes, tops.
Do other people agree?