I admire inventors who have studied a problem, and then by their creativeness and perseverance, find a solution. Along the way to finding that solution, their invention in many instances is the product of trial and error.
However, in my view the most interesting inventions are those that were created by accident. One of my favourites from the 20th century is Superglue.
In 1942 during WW2, a chemist named Harry Coover was researching and discovering materials to use for a plastic rifle sight, as part of the US war effort. One of the compounds he considered, Cyanoacrylate, was durable but stuck to everything it touched. Whilst Cyanoacrylate was not suitable for the plastic rifle sight, many years later in the 1950’s, Coover and a fellow researcher Fred Joyner repurposed Cyanoacrylate as an adhesive, that is commonly known today as Superglue.
This accidental discovery has led to Superglue being used in a wide variety of applications the most notable being as a quick, and inexpensive repair adhesive you can buy in a $2 store. However, its application is quite varied, with just some examples being as an eyelash extension glue, a model building adhesive, and as a forensic tool to capture latent fingerprints on non-porous surfaces. One notable use, due to its ability to bond human skin, was as a cyanoacrylate spray first used in the Vietnam War to reduce bleeding in wounded soldiers until they could be taken to a hospital. Quite an impressive accidental invention.
If you wish to see more, just do an internet search for “accidental inventions”, as there are many notable accidental inventions.