Frankenstein. The epitome of regretting your creative choices. Always considered a work highlighting the dangers of playing God, the book actually has another message: think clearly about your decisions because you may become synonymous with them later.
You shouldn't have to look back on your work with regret. Everything you do, in a perfect world, should make you feel proud and want to stand up shouting "I DID THIS" not try and find the darkest corner of a room and hope no one notices.
That's not to say the fame and fortune you receive from your creation doesn't make the work worth it, just that you may grow to hate and revile the monster you've created, especially when it chucks little girls into lakes.
This regret isn't limited to fiction, there are a plethora of examples of people who looked on their work and wished for an undo option...
Alfred Nobel invented dynamite. The man for whom the peace prize is named after invented dynamite. Not only that, the original name for his super peace loving invention was 'Alfred Nobel's Safety Powder'; one of the greatest misnomers since the Reliant Robin.
Wanting to devise a safer explosive, another brilliant misnomer, Nobel created dynamite as a less volatile substitute to nitroglycerin, and if you've ever played Crash Bandicoot you know how volatile that stuff is.
A life long pacifist, Nobel believed that that the creation of dynamite would sicken the world into never starting another war again, stating: “My dynamite will sooner lead to peace than a thousand world conventions. As soon as men will find that in one instant, whole armies can be utterly destroyed, they surely will abide by golden peace.” And as we know from our two centuries of unbroken peace his plan worked out.
It seems Nobel only had a change of perspective when, after his brother Ludvig died in 1888, Alfred's obituary was accidentally published instead: in the face of being referred to by a French newspaper as 'the merchant of death', he became concerned for his legacy. And indeed Alfred Nobel managed to change how he was remembered, setting aside the vast majority of his wealth to be distributed as prizes for physics, chemistry, medicine, literature and the establishment or furtherment of peace – though he did not think the Nobel Peace Prize would accomplish any tangible peace. He was really betting on dynamite.