A version of how a pessimist, optimist and realist see things is a saying that has been printed on many images. This saying was posted on the newsgroup freeware news on April 20, 2007:
 
“The pessimist sees darkness in the tunnel, the optimist sees light on the tunnel’s end, the realist sees the lamps of coming train, the engine driver sees three idiots on the rails.”
   
American author James Branch Cabell (1879-1958) is frequently credited, but what he wrote in The Silver Stallion (1926) is, “The optimist proclaims that we live in the best of all possible worlds; and the pessimist fears this is true.”
   
“The optimist sees a light at the end of the tunnel, the realist sees a train entering the tunnel, the pessimist sees a train speeding at him, hell for leather, and the machinist sees three idiots sitting on the rail track” is sometimes credited as a “German saying,” but no German source is known.
   
         
Wikiquote: James Branch Cabell
James Branch Cabell (14 April 1879 – 5 May 1958) was an American author of satirical fantasy works, most notably The Cream of the Jest, Jurgen : A Comedy of Justice, Figures of Earth, and other works in the series known as Biography of the Life of Manuel.
(...)
The Silver Stallion (1926)     
Yet creeds mean very little… The optimist proclaims that we live in the best of all possible worlds; and the pessimist fears this is true. So I elect for neither label.
. Coth, in Book Four : Coth at Porutsa, Ch. XXVI : The Realist in Defeat
 
TV Tropes—Quotes / Sliding Scale of Idealism vs. Cynicism
The optimist sees a light at the end of the tunnel,
the realist sees a train entering the tunnel,
the pessimist sees a train speeding at him, hell for leather,
and the machinist sees three idiots sitting on the rail track.
— German saying
(...)
“The optimist proclaims that we live in the best of all possible worlds; the pessimist fears this is true.”
— James Branch Cabell, The Silver Stallion.
 
Google Groups: freeware news
2007-04-20
L. Toldy
4/19/07
(...)   
>> The pessimist sees darkness in the tunnel, the optimist sees light on the tunnel’s end, the realist sees the lamps of coming train, the engine driver sees three idiots on the rails.
>> A pesszimista a sötétség et lát ja az alagút ban, az optimista a fényt az alagút végén, a realista a közeledõ gö vonat lámpáit, a mozdonyvezetõ pedig három idiótát a sín eken
 
Twitter
Adam VanderZwan‏
@Adamvanderzwan
The pessimist sees a dark tunnel. The optimist sees a light. The realist sees a train. The train conductor sees three idiots! XD
7:16 PM - 7 May 2009
 
Twitter
Ralph Talmont‏
@ralphtalmont
Pessimist sees a tunnel; optimist sees the light @ the end; realist sees a coming train. Machinist sees 3 morons in the middle of the tracks
4:35 PM - 14 May 2009
   
Google Groups: alt.hvac
You be a Judge
Grumpy
2/15/10
Pessimist sees all in black
Optimist sees light on the end of tunnel
Realist sees locomotive coming at him
Conductor sees three idiots on the tracks
—- news://freenews.netfront.net/ - complaints: .(JavaScript must be enabled to view this email address)—-
 
Twitter   
Bernadette Borrelli‏
@I_Am_Bernadette
A pessimist sees darkness; optimist sees light; realist sees light & the coming train.Train driver just sees 3 idiots sitting on the tracks!
12:29 PM - 26 Jun 2010
 
Twitter
Mwaniki Gachoki‏
@gmwaniki
A pessimist sees
darkness,optimist sees
light,realist sees light & train,train
driver sees 3 idiots sitting on the
rails.
12:47 PM - 27 Jun 2010
 
Twitter
Emenike‏
@Dennis_UT
Pessimist sees darkness, Optimist sees light, Realist sees light & the coming train! Train driver sees 3 idiots standing on the rails.
2:29 PM - 26 Mar 2011
   
Twitter
Abed Nasser‏
@AHN_LB
Pessimist sees dark tunnel,Optimist sees light at da end of tunnel,Realist sees freight train,Train operator sees 3 idiots standing on track
7:01 AM - 17 Apr 2011
 
Twitter
Akhil Sunny‏
@akhilsunnyv
pessimist sees a dark tunnel
optimist sees a light @ d end of tunnel
realist sees a train
train operator sees 3 idiots standing on d tracks
3:26 PM - 20 Apr 2011
 
Twitter
Arya_아리아‏
@Ary4_Sh1n
PESSIMIST sees a dark tunnel
OPTIMIST sees light at the end of it
REALIST sees a train
TRAIN OPERATOR sees 3 idiots standing on the tracks
4:52 AM - 5 Nov 2011
 
Twitter
D.B. Warren‏
@DeltaBravoPhoto
A pessimist sees dark in a tunnel
An optimist sees light
A realist sees a train
A train engineer sees three idiots standing on the tracks…
10:42 PM - 2 Jun 2013
   
Twitter   
Wayne Colvin‏
@waynecolvin
the pessimist sees a train speeding at him, hell for leather, and the machinist sees three idiots sitting on the rail track.” - German joke
4:41 PM - 1 Mar 2014
 
Twitter
Torch82‏
@miketorch82
... The train operator sees three idiots standing on the tracks.
1:33 AM - 7 Jun 2014
 
Reddit—Jokes
What’s the difference between a optimist, a pessimist and a realist?
submitted April 11, 2015 by KevinThePirate
The optimist sees the light at the end of the tunnel. The pessimist sees nothing. And the realist sees the train.
COMMENTS
SamTheDude16
Its actually “a pessimist sees a dark tunnel, an optimist sees light at the end of the tunnel, a realist sees a train, and the train operator sees three idiots standing on the tracks.”
 
Twitter
Suzannes‏
@teach22112
Pessimist optimist realist train operator sees three idiots standing on the tracks | http://starecat.com  http://starecat.com/pessimist-optimist-realist-train-operator-sees-three-idiots-standing-on-the-tracks/ …
9:50 AM - 11 Nov 2015
     
Reddit—Jokes
The pessimist sees the dark tunnel.
submitted November 6, 2017 by madarasi012
The optimist sees the light at the end of the tunnel.
The realist sees two lights at the end of the tunnel.
And the engineer sees three idiots standing on the tracks.
 
Reddit—Jokes
Deep.
submitted November 29, 2017 by Jem_Jmd3au1
Pessimist sees nothing but dark in the tunnel.
Optimist sees light in the end of the tunnel.
Realist sees light from incoming train.
Engine-driver sees three idiots standing on the track.