Hello.
I’m just wondering if uilleann pipers can feel vibrations of the instrument as you play.
Can you feel the vibrations in the chanter? Do the drones make your liver quiver?
Intensity?
That would just seems like the bee’s knees.
Also, I have the impression that pipers rarely smile or laugh while playing. Is that true? Is it the nature of the instrument or the nature of the pipers?
What part of surly do you not understand? 
Seasoned pipers grimace less than novice pipers. Great pipers exhibit the occasional wry smile.
That’s true. Someone ought to do a study of “piper’s face”. The tense rictus on the lips, eyes cast up toward the ceiling. And don’t forget to grunt while you play. 
Maybe they are worried about the reeds-
Is the air too dry?
Has the G gone flat?
How did pipers survive before Xanax anyways?
I get panic attacks just thinking about starting to learn UPs!!! 
Most pipers do not smile or laugh… ever. It’s the path towards enlightenment, you know you’ve reached the highest level when you can handle anything life throws your way:
The great pipers are not only smiling but looking around the room and holding conversations as they play. Unbelievable. 
After 11 years, I can sometimes manage not to grimace, but if you ask me to say anything more than “hup!” I come crashing to a halt.
The facial expressions occur because it takes lots of concentration to play the pipes. Initially, when you first learn, you are concentrating very hard on the physical mechanics of the instrument. Hence, you are grimacing. Then your focus shifts to musical mechanics: rhythm, tone, ornamentation, keeping your speed constant, etc., etc. Hence, you are grimacing. Eventually (and we are talking decades here), the physical and musical mechanics move into the background of your brain and you are mostly trying to remember how the d**n tune starts. Hence, you are grimacing. And of course at any point, your reeds may be acting up. In which case, you will be grimacing.
At this point, most of my concentration is focused on NOT thinking about anything while I play – not my elbows, not my fingers, not the regs, not ornaments or anything else, just hearing the music. If I can find that zone, I am usually not grimacing. But if I suddenly have to think about something… 
And yes, in a well-made set, the drones buzz all the way up into the bag, and the chanter talks back to your fingers. And yes, it IS the bee’s knees!
KAD
Thanks all for the great responses.
From now on, I’ll focus on the fingers and elbows and shoulders and such while watching videos. Although I think it’s quite natural to be drawn to facial expression of those in distress.
Now where did I put that quart jar of mixed benzodiazepines??
My fella all-too-frequently advises me that I’m displaying “the piper’s snarl.” I do have to add that, at least in my case, besides the intense concentration I feel a definite physical link between my trapezius & deltoid muscles and those in my face. When I have to really put pressure on the bag or the reed is super-hard, my lip seems to curl in sympathetic response. It’s almost like a tic! But I’m working on it. My goal is to be a lovely cool customer like this guy:
http://www.youtube.com/watch?v=AOjYKx4LMkc&feature=relmfu
Though if you look really closely, even Mr. O’Flynn squinches his eyebrows once or twice!
One more clip, of two of my favorite pipers who can play anything. Bear in mind that they’ve been up all night(s) and probably had more than one or two pints. 
The piper on the left is so contained he can probably quote Shakespeare while he plays, and I’m willing to bet the piper on the right is athletic enough to stand on his head while he’s at it (I’ve seen him come close)! Anyway, these two guys support what KAD says. Even though they’re kind of on another planet here, they’re among the great ones who can practically make you a cup of tea in the middle of a set.
http://www.youtube.com/watch?v=-gP6VPQjUdA&feature=channel&list=UL
P.S. And oh, yes, for me it’s ALL about the vibrations. I’ve played flute all my life but the pipes feel like they’re a physical extension – like, well, breathing. The flute never really has for me, even though I can feel it buzz in my hands. The pipes are just so alive.
Firstly, I enjoy Ms. Wilde’s contributions, always to the point and a bonne point - risking approbium for my french.
I agree entirely, uilleanne piping is the full wrap around, fourth dimension, vibrating experience.
My aside: my nuance to the facial grimace, is a full, silent, immitation of the vocalisation of the tune; all jaw chewing, head spinning, shoulder turning, eye popping, like the hunch back of notre damme, trying to get the vibrations right. Don’t get many gigs though.
My goal: to get to the point of two pipers I know (in 30 years) who can hold a full conversation whilst playing a three tune set with all the variations and reg accompanyment, though otherwise moving apparently no other muscles.
More seriously, to play with others in noisey rooms, requires feeling the vibrations, rather than hearing the notes?
Pwrt
As for the liver only left handed players. Proximinity is essential.