I was reading this and thinking are there more examples of situations like this? It is kind of interesting. The Legend of the 'Unsolvable Math Problem' | Snopes.com
The ski jumper who was infamous for years as “the agony of defeat” in the opening credits to Wide World of Sports had no idea that he was world-famous for having stuffed it into the crowd standing alongside the jump until years later. Not sure if that counts…
Huh, OK, when I saw the thread title I was all set to look up that very example. Never mind, then.
EDIT: That was in response to the OP, not to Ethilrist.
There’s a whole list for them on the TV tropes page Achievements in Ignorance.
Scroll down to the bottom for the “real life” examples. The OP is the first example on their list.
Cliff Young didn’t seem to think that winning a marathon against runners less than half his age would be anything more than chasing after sheep for endless hours as he’d been doing all his life.
Yeah that was where I first found it 
I thought it was the most interesting example by far though as the rest of the examples didn’t seem that important. The magnet thing sounds cool but it probably didn’t happen in the manner described.
How far back do you want to go? I mean, I really doubt Bunga the Caveman knew what the end result of his taming fire would be. (Hint: everything!) The first guy to write something down in the dirt, or paint on a cave wall, was probably not aware of the world-changing importance of the skill of writing. Lots of things were invented/discovered/tried by people long ago, that ended up having a huge impact on the future. Prehistory is gonna be full of these kind of events!
Well I am kind of interested in the stories where, say, caveman A noticed caveman kid B rubbing two sticks together and suddenly creating fire. Whereas before they only get fire when it comes naturally from lightning or whatnot, caveman A is excited and grunts at Caveman B, “How in the blazes did you do that?” Caveman kid B squeaks back, “Oh is this something special? I just like it because it looks pretty.”
I just happened to read (in George Tyson’s Turing Cathedral) that when Heinrich Hertz discovered radio waves, he was sure they would never be of any importance.
Of course, Fleming noted the antibiotic action on Penicillium mold but dismissed it.
And famously, G.H. Hardy was sure that none of his number theory could ever have practical import.
Cool that reminds me of the laser, I think they called it the solution looking for a problem.
No, no!
“FIRE bad, TREE pretty!”
Not only is it the most interesting example, a couple of the others made me want to call out “cite?”
Particularly this one:
“It was once thought” may or may not be true, but by the time Bannister achieved it I doubt if anyone involved in athletics held that view. The record was already (I think) 4:01.4, so there was no reason to think it wouldn’t be broken at some stage.
To then make the stretch that Bannister beat the mark because he was “an amateur runner who never heard of this ‘fact’” is ridiculous. Of course he was an amateur - if you wanted to compete in the Olympics you had to be in those days. In fact he had already competed in the 1952 Olympics.
Your intuition is good, but it is even worse than you think. The quote from TVTropes is quite wrong. It was no accident. Bannister very deliberately and systematically set out to break the four minute mile “barrier”.
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To the OP’s question, there are lots of stories of accidental scientific discoveries, but in most cases they were not really quite so accidental as some versions of the story make it appear, and, in general, the scientist did at least to some extent recognize the significance of his discovery, even if he was not quite expecting it - otherwise it would probably not have been recorded at all.
However, the “discoveries” of oxygen by Hales, Scheele, and even Priestley might count. Scheele and especially Priestley knew they had something interesting (Hales probably not so much), but the real significance of oxygen, its role in combustion and respiration, and the notion of it being an element, was not realized until until Lavoisier reinterpreted Priestley’s findings.
Penzias and Wilson were looking for the cause of some noise in an antenna. It turned out to be the [discovery of cosmic microwave background radiation](Discovery of cosmic microwave background radiation).
Well, yes, but they realized that, right? It was the realizing that got them the Nobel Prize. Otherwise they would just be two guys who tried to fix a staticky antenna, and failed.
As I said, there are lots of stories of accidental discoveries in science, but usually the discoverer realized he had discovered something important (the ones where he didn’t, we never got to hear about), and, as I understand it, that is not quite what the OP is looking for.
There’s actually a very good reason why Fleming never did anything much with Penicillin - it was an absolute bitch to work with. Its eventual commercialisation required a lab-full of scientists of various specialities, four years, and the motivation of WWII and battlefields full of soldiers who could really REALLY use something better than sulfanilamides. Fleming, all by himself, just didn’t have the skill set.
I nominate Columbus’ discovery of America. Suer, he was trying to do something difficult and important at the time, it was just a different difficult and important thing than the one he ended up doing.
According to this article Bannister was probably not even the first person to break the 4 minute mile.
Short version is people seem to have been breaking the 4 minute mile at least 200 years ago but not as part of amateur athletics which is what Banisters record is in regard to.
I doubt that Columbus realized the impact of The New World.
I would love to bring Shakespeare back. He wrote for the masses, looking only to make a living, and I think he would be absolutely flabagasted that his plays were still being performed.
Here is the proper link: Discovery of Cosmic Microwave Background Radiation
No. They didn’t realize it, someone told them.
How is that not realizing?
If Burke had told them “What you are seeing must be this microwave background stuff Peebles has been talking about,” then he would have been doing the realizing, and he would have deserved to be a co-author and have a share in the Nobel, but that isn’t what your quote says happened. It says he mentioned Peebles’ work to them, and they made the connection.