If anyone tells you that all you need to do to succeed is work hard, just mention Carl Wilhelm Scheele. They will say, "Who?" And your point will be proved. This may be the most accomplished chemist never to get credit for anything — except possibly accidentally killing a dictator.
Carl Scheele didn't have a bad life. Other than dying young — although forty-three was a fairly decent age for a chemist in the 1700s — he met with relatively little calamity. Born to a wealthy and locally prominent family in 1742 in what is now Germany, he was tutored by educated friends of his father. Eventually he became an apothecary, which allowed him to pursue his interest in chemistry. The people around him recognised his scientific talent, and he was elected to the Royal Swedish Academy of Science, though he didn't go to meetings.
That was a mistake. So was his reluctance to publicise his work. Scheele devised a way to study the properties of organic acids, precipitating them with lead or calcium salts before dissolving them again in new acids. By working steadily and carefully, he discovered twelve different acids. He turned his attention to metals and isolated several of them, including barium and molybdenum.
Most impressively, he was able to isolate oxygen well before the much-more-famous Joseph Priestley. He's not as well remembered because he didn't publish until after Joseph Priestley. In fact, due to his lack of contacts among academic scientists and his relatively early death, he hasn't received proper credit for nearly all of his discoveries.
Except one. Carl Scheele managed to keep his name attached to Scheele's green. Mix sodium carbonate and arsenic oxide together in a solution and you get sodium arsenic — a combination of sodium, arsenic, and oxygen. That gets mixed in with copper sulfate to produce a copper arsenite precipitate which can cheaply and easily dye material green.
Scheele's green became a famous, and then an infamous, pigment, because of the presence of arsenic. The first of its possible victims was Scheele himself. Like most 18th century chemists, he tasted his own creations. The dye poisoned people well into Victorian times.
In 1982, British chemist David Jones famously speculated that the green wallpaper hung in Napoleon's residence in St. Helena poisoned him with arsenic and led to his death. The theory is much-disputed, but also very popular. Which makes Carl Scheele's story the perfect way to illustrate that hard work and real accomplishment are worth little if you don't have popularity on your side.