Originally Posted by Andy M.
While cooking in the shell may impart more flavor, there are circumstances where I don't want shrimp served to me in the shell or even with the tail piece attached. If I'm eating a pasta dish with shrimp, my fingers shouldn't have to get involved with the shrimp. There are more informal occasions when I don't mind eating with my fingers. Then it's OK.
True story: Years ago when I was living in Atlanta, I was dining at my favorite super-posh Italian restaurant (a place that looks like something right out of The Godfather). We were with a large group of my girlfriends celebrating someone's birthday, and our waiter Tony was having fun entertaining us.
I ordered the shrimp scampi, and having good Southern ladylike table manners didn't want to fish around in my pasta with my fingers to remove the tails. So I struggled with my knife and fork to gingerly remove the tail, when my shrimp suddenly broke free, slipped through the buttery sauce and flew across the table. Tony was watching all of this, highly amused, then stepped in to assist me before I (in his words) "hurt someone". He then taught me a technique that I use to this day.
Take the flat side of the dinner knife (the one without the teeth of course) and press it into the joint of the tailfin and the tail. Then stab the meat with your fork, pull gently and....voila.