I went to rewatch that and came across an earlier work by the same guy called Pony about a little girl who gets a “magic pony” for her birthday…sort of…
I think I may be traumatized for life.
Thanks.
I guess my coffee had not yet kicked in.
Does the cartoon that opens Who Framed Roger Rabbit count? That was absolutely hilarious.
Too many to choose from, but I’d have to say my favorite is Pixar’s Presto. I was laughing so hard the first time I saw it my daughter thought my head might actually explode. It as funny on repeated viewings. 
I had to think about for a while. Duck Amuck was certainly up at the top of the list, along with Rabbit Fire and Rabbit Seasoning, where Bugs and Daffy start the ‘Rabbit Season’ - ‘Duck Season’ gimmick. But since Chuck Jones got so much coverage in this thread already, I wanted to find something outside of the Looney Tunes universe.
So my final selection, Roger Myers’ Scratchtasia
I can’t pick just one.
The most haunting animation I know is Mindscape.
The Sand Castle is a very whimsical short.
That cartoon gave me an idea what true psychosis might be like. Disturbing.
The Rabbit of Seville
(My autographed copy of*** Chuck Amuck*** is one of my most prized possessions.)
Me too 
Yuriy Norshteyn’s Hedgehog in the Fog
The first animated short that always comes to my mind is…
Simpsons, for what it became
I’m not sure if I can say it’s my favorite of all time yet, but I absolutely loved the “Day and Night” short that ran before Toy Story 3. Such a fantastic blend of 2D and 3D animation. So simple and yet so beautifully complex at the same time.
Also seconding “For the Birds.”
EDITING TO ADD:
If you haven’t seen any of "Day and Night, here is a short clip.
If you liked that, check out this other one by him, “Billy’s Balloon”
One of my favorites from Allegro non troppo, a collection of animation set to classical music:
Probably the most touching, though, is Disney’s The Little Match Girl. The lousy youtube dub doesn’t do it justice, of course.
The very early Pixar one with the momma desk lamp and the baby one bouncing around.
So when I change my sig to “Mah spoon is too big!!!” I won’t just be crying out in the wilderness?
How about “I am a consumer whore! (and how!)”?
As long as it’s not “My anus is bleeding!”
If you have a few minutes for some casual YouTubery, do a search for all the “My spoon is too big” videos. There are some entertaining (and some awful) homespun versions of that bit.
Damn close second in my book. My personal favorite is Linda McCartney’s The Oriental Night Fish, which was shown right before Bakshi’s Lord Of The Rings when it premiered in Hollywood.