“Thank God It’s Friday” (TGIF) had led to other acronymns.
 
“So/Sure Happy It’s Thursday” is a backronym (back acronym) of the word “shit” that has been printed on many images. “Sure Happy It’s Thursday” has been cited in print since at least 1967 and “So Happy It’s Thursday” since at least 1971.
   
“S.H.I.T. F.I.T. (So Happy Is Thursday. Friday Is Tomorrow)”—“shit fit”—was posted on Twitter on July 26, 2012.
   
 
10 March 1967, San Diego (CA) Union, Frank Rhoades column, pg. B-6, col. 1:
From Encinitas’ 6-member Sure Happy It’s Thursday Club ...
 
29 January 1971, Hazleton (PA) Standard-Speaker, “Highacres Happenings,” pg. 4, col. 5:
Yesterday a “So Happy It’s Thursday” was held.
 
26 June 1975, Honolulu (HI) Advertiser, Tom Horton column, pg. A-3, col. 1:
... and start the weekend on Thursday afternoons, T.G.I.F> (Thank God It’s Friday) gives way to Sure Happy It’s Thursday.
 
29 April 1981, Seattle (WA) Times, “Grim Humor” by Walt Evans, pg. D2, col. 1:
At a potluck luncheon they put up a big wall banner, which P. J. Allyn brought by, “So Happy It’s Thursday,” the banner read.
 
Google Books
Broadcast Copywriting as Process:
A Practical Approach to Copywriting for Radio and Television
By J. Clark Weaver
New York, NY: Longman
1984
Pg. 45:
To be able to endure the Monday through Friday routine, the “thank God it’s Friday” and “sure happy it’s Thursday” exclaimers tend to plan for, and achieve, release on the weekend.
   
Google Groups: net.jokes
Acronyms (offensive language)
EAI—sideways, sort of—
9/12/84
(...)
Then you know what TGIF means, so how about:
 
Sure Happy It’s Thursday!   
 
Google Groups: rec.humor
days of the week
Brown, William J.
7/12/92
(...)
SHIT= Sure Happy It’s Thursday
   
Google Groups: rec.arts.tv.soaps
DOOL: From whence Carly?
.(JavaScript must be enabled to view this email address)
9/17/92
(...)
A very happy it’s SH*T day Quince   (Sure happy it’s Thursday)
 
Google Groups: alt.drunken.bastards
drunken bastard in pain
Ian Michael Boisvert
12/16/93
Alright, I’ve got a DB story to tell.  It was the last day of school and, of course, everyone wanted to get pissed to the gills.  So, everyone migrated to one of the parties that was happening on campus (a SHIT - Sure Happy Its Thursday) and proceeded to get inebriated.
 
12 September 1999, San Francisco (CA) Chronicle, “On the Job, Xers Just Want To Have Fun” by Auren Hoffman, pg. 10:
So Happy It’s Thursday (the acronym we use is not appropriate for a family newspaper).
   
27 May 2003, Daily Herald (Arlington Heights, IL), “Growing world of acronyms is a shortcut to more snafus” by Burt Constable, pg. 9:
The Daily Herald archives include MADD and GLAD, PADS and RATS, WINGS and DARE, RISE and BOOST, FACE and NOSEE and even a local Mensa smart-alecky club that meets every first Thursday of the month for an outing they call Sure Happy It’s Thursday, which I would consider a Crude, Rude, Acronym Practice.
 
Twitter
RaggedEdge‏
@RaggedEdge
Instead of TGIF today is Sure Happy It’s Thursday.  I’ll leave everyone to figure out the acronym on their own 😊
7:31 AM - 5 Apr 2007
 
Twitter
Oz‏
@bnsrf
S.H.I.T!!! So happy it’s thursday!
11:37 AM - 9 Aug 2007
 
Twitter
gratefullab‏
@gratefullab
S.H.I.T. - So Happy It’s Thursday!  Got lots to do - but ready for the challenge!
10:50 AM - 28 Feb 2008
 
Twitter
Byron Wilkins‏
@tr1byron
Sure. Happy. It’s Thursday.  The capital letters say it all… 😊
7:27 AM - 22 May 2008
 
Urban Dictionary
So Happy It’s Thursday
A way to say shit when you can’t openly swear.
Bill, did you forget to turn in your TPS report? So Happy It’s Thursday! I forgot.
#s.h.i.t #sugar honey iced tea #shit #crap #poop
by chipf70 January 30, 2011
 
Twitter
hrdrs ♛‏
@imLAndre
S.H.I.T. F.I.T. (So Happy Is Thursday. Friday Is Tomorrow)
1:41 PM - 26 Jul 2012
 
Twitter
Dev‏
@devinnann
So happy it’s Thursday cause Friday is tomorrow!!
2:27 PM - 26 Jul 2012
 
Twitter
Ashley Walters‏
@ashleysirettdc
S.H.I.T F.I.T (so happy its thursday..friday is tomorrow!)
4:54 PM - 26 Jul 2012