I nominate O Carolan’s “Farewell to Music”
pastorkeith
I nominate Danny Boy. 
Amazing Grace.
Too many gone on before–I can’t hear that tune on pipes or fife without tearing up now.
–James
Somewhere Over the Rainbow, especially Tiny Tim’s version.
I like “A Fig for a Kiss” if played slowly (aka Matt Molloy). It’s turning into my favorite flute tune - yes, I’m a bi-woodwindian!
And we’re SUPPOSED to be sad - we’re Irish, by God!!!
Pat
Well, I’m neither sad nor Irish. I do like to have a good cry from time to time, though.
The Foggy, Foggy Dew
Dont know if it’s sad or very stirring…but Davey Spillane’s playing of Lament for Cuchullain on Uilleann Pipes (from Riverdance)…does me in every time I see it …
Killkenny from the Music at Matt Molloy cd.
Afscheid van een vriend (Clouseau, Belgian Band)
My whistle playing makes my wife sad (unintentially )
One the one hand I think it’s a bit of a silly exercise, it’s a good musician who puts his touch of sadness on the tune, not necessarily the tune itself.
But Caoineadh na tri Mhuire song by Joe Heaney always worked for me, it’s a simple tune without touching the obvious minors yet it touches the right emotions. My son learned it from Noel Hill in concertina class a few years ago and he did a nice job on it too.
Another keen, Caoineadh Inion ui Mhuiriosa, sung by Labhras O Cadhla is anther one that does it for me.
Another all time favourite, maybe not for sadness, it is a love song, is By the River of Gems, when played by Seamus Ennis anyway it brings the tenderness but also the tinge of sadness love brings. Maybe I am pre occupied with the tune at the minute as I’ll be teaching it to a few young pipers tonight and I am just after renewing my acquaintance with it.
But again, it’s not necessarily the tunes, it’s what the player brings to it: Martin Rochford could send the shivers down my spine more than anyone when he played the fiddle in his kitchen. Tommy Potts’ music has it as has some of Tommy Peoples’.
“The Sadness of Some” by Sarah Bauhan.
Clare’s Reel by Sylvain Barou. A tune made for the flute.
Dark woman of the glen.
After the Battle of Aughrim. I can just see the bodies strewn all over the field.
Anything in D minor. It’s the saddest key of all.
..
Are we talking tunes or songs?
With tunes I agree that it depends on how it’s played.
For songs, I’ll put in a nomination for The Green Fields of France. 
And as far as being Irish means we’re sad, I think that’s a bit limiting. We can also be angry. So it’s either sad or angry… and drunk, no? 
Admittedly though, I don’t drink.
Jason
Carrickfergus and Isle of Inishfree
Tunes, according to the thread title.
But if we were to talk songs, I’d say “Kilkelly Ireland, 1860”.
I personally hate most musicals. That said, “Sunrise, Sunset” from ‘Fiddler on the Roof’.
(Tevye)
Is this the little girl I carried?
Is this the little boy at play?
(Golde)
I don’t remember growing older
When did they?
(Tevye)
When did she get to be a beauty?
When did he get to be so tall?
(Golde)
Wasn’t it yesterday
When they were small?
(Men)
Sunrise, sunset
Sunrise, sunset
Swiftly flow the days
Seedlings turn overnight to sunflowers
Blossoming even as we gaze
(Women)
Sunrise, sunset
Sunrise, sunset
Swiftly fly the years
One season following another
Laden with happiness and tears
(Tevye)
What words of wisdom can I give them?
How can I help to ease their way?
(Tevye)
Now they must learn from one another
Day by day
(Perchik)
They look so natural together
(Hodel)
Just like two newlyweds should be
(Perchik & Hodel)
Is there a canopy in store for me?
(All)
Sunrise, sunset
Sunrise, sunset
Swiftly flow the days
Seedlings turn overnight to sunflowers
Blossoming even as we gaze
Sunrise, sunset
Sunrise, sunset
Swiftly fly the years
One season following another
Laden with happiness and tears