Kamran Loghman worked for the FBI and helped turn pepper spray into weapons grade material. He also wrote a user guide for police departments.
In 2011, police sprayed pepper spray on docile protestors. Longman's reaction was, "I have never seen such an inappropriate and improper use of chemical agents."

Pepper spray

Tim Berners Lee developed HTML and created the World Wide Web, but his major regret relates to the '//' at the beginning of every web address.
"Really, if you think about it, it doesn't need the //. I could have designed it not to have the //," he said.

The double slash

Working as an employee of web host Tripod, Ethan Zuckerman wrote the code to launch the pesky pop-up add.
In an essay entitled "The Internet's Original Sin," he took full responsibility for the hated tool. He later explained that he was sorry. Their intentions were good.

The pop-up advert

Vincent Connare, the designer of the font Comic Sans, said, "If you love it, you don't know much about typography. If you hate it, you really don't know much about typography, either, and you should get another hobby."
Connare's point is that Comic Sans is overused and misused. It was designed for a Microsoft application aimed at children to replace Times New Roman in speech bubbles.

Comic Sans

Tom Karen designed the Raleigh's Chopper, one of Raleigh's best-selling bikes in the 1970s. It was loved for its comfortable saddle, laid-back seating, and Harley Davidson-Esque handlebars.
However, Tom Karen describes it as "terribly heavy so you wouldn't want to ride it very far."

Raleigh Chopper

<ul>
<li>J. Robert Oppenheimer, director of the Los Alamos Laboratory during World War II, is credited with the creation of the atomic bomb. Oppenheimer does not regret playing a part in the war effort, but he feels that the way the atomic bomb was used wasn't right. Japan could have been warned about what the bomb meant.</li>
<li>Albert Einstein, who made the bomb possible, believed Germany was attempting to create an atomic bomb to use against the allies in World War II. He later regretted it. He said had he known that the Germans would not succeed in producing an atomic bomb, he would not have proceeded.</li>
</ul>

The atomic bomb

Mikhail Kalashnikov designed the rifle for the Russian army. It was a simple and cheap automatic rifle that caused more deaths than any other assault rifle.
Kalashnikov later wrote in a letter to the head of the Russian Orthodox church, "If my rifle claimed people's lives, can it be that I…, an Orthodox believer, am to blame for their deaths, even if they are my enemies?"

AK-47

John Sylvan's invention of coffee pouches gave rise to systems like Nespresso and Tassimo and make it very easy to grab a caffeine fix.
"I feel bad sometimes that I ever did it," he said a few years ago. "It's ... a single-serve delivery mechanism for an addictive substance."

Coffee capsules

Flappy Bird was a crude and simple game that proved to be hugely addictive. After 50 million downloads and advertising revenue of around $45,000 a day, creator Dong Nguyen had enough and withdrew it from the app stores.
The game attracted the press and Nguyen was besieged with calls, tweets, and emails. He tweeted, "I cannot take this anymore."

Flappy Bird

Bob Propst introduced America to the open-plan office along with the office cubicle.
Companies saw his invention as a way to save money. Propst came to regret his creation, saying cubiclizing people in modern corporations is "monolithic insanity."

The office cubicle

Just because someone's invented something, it doesn't mean that they're happy with the end result. 1. J. Robert Oppenheimer - The atomic bomb. It's J. Robert Oppenheimer who, as director of the Los Alamos Laboratory during World War II, is credited with the creation of the atomic bomb.