Customer wants espresso over ice. Store doesn't want to do espresso over ice.
Customer orders espresso and a separate glass of ice - barista expresses gentle displeasure. Customer proceeds to be a bit of a dick (he admits as much in the post).
It's an interesting study (particularly if you follow some of the other links and comments) into the tension between artisan coffee shops and the general populace. I quite enjoy taking my coffee as the barista suggests, it often opens me up to new experiences. In this case, they also believe in maintaining a standard.
But of course, when your customer is not an aficionado, you run into trouble - they just want it how they want it.
http://andiamnotlying.com/2008/murky-coffee-arlington-hold-that-espresso-between-your-knees/