Every businessperson makes mistakes. Australia's David Yuile's cost him A$1.3 million ($1.41 million) in a day.
The chief executive of telecommunications company AAPT jointly started a CRM consultancy in London in the mid-1990s.
They decided to sell to Interliant, a US-listed company, in a deal including thousands of shares.
"We sold in 1997, just before the tech-wreck when our shares were worth US$12 ($13) each," Yuile recalls.
Over the next few months the then-27-year-old watched his shares price skyrocket. He became a paper millionaire.
"It went up and up and up, reaching US$70 a share at one point and putting my shareholding's worth between £2.5-3 million ($5-6 million), but I held too long, the stock market started crashing, I lost £700,000 ($1,384,880) in one day and ended up selling for five cents a share.
"The good thing is I was young and starting businesses at that age means you can pick yourself up and do it again ... I kept my house, I just wish I could have been a bit richer."
Yuile's other regret happened when he was boss of Powertel, which was later sold to AAPT.
Today AAPT, a division of Telecom New Zealand, turns over about A$400 million ($435 million) annually.
"We were trying to build an ESL broadband-to-homes business and you had to have pretty good coverage to work because people were pretty spread all over Australia," he says.
"We were doing things incrementally to boost our coverage; 10 more [coverage] areas here, 12 more there. Then, nine months later, rival company TPG rolled out and we were left going 'oh bugger'.
"In the end it wasn't even a tortoise and the hair race as they barrelled past us with about 300 coverage areas to our 70 or 80.
"Looking back I should have been so much more of a believer and pushed harder to expand our network."
Perhaps unsurprisingly, TPG becomes AAPT's owner from February 28. "The cycles of business," Yuille quips.
Foodco Group boss Serge Infanti says what doesn't ruin you makes you stronger - if you accept and learn from mistakes.
"Any businessperson who claims to know it all and see the future with absolute clarity is kidding themselves," says the managing director and part-owner of the Australian owned company, which today has more than 450 franchise outlets worldwide trading through the Muffin Break, Jamaica Blue and Dreamy Donuts brands.
Infanti started as the franchisee of a Muffin Break outlet in Queensland in 1990.
He says his only business regret is he didn't fast-track the group's launch in Asia. Foodco currently has 26 outlets in China, two in Singapore and expects to launch in Malaysia this year.
"Of course there is a graveyard of many Australian businesses that went overseas and failed, so we had to temper our plans. But if I had my time again I would have found some money to accelerate expansion to China, which has this huge rising middle class with aspirations and desires of a Western lifestyle and coffee drinking is very much a part of that," he says.
"We went into the UK market and in the early 2000s started due diligence for China but we started with a very conservative approach and should have seen opportunity to push the button faster, been more entrepreneurial in finding more money to roll out more quickly because the speed of China's migration from tea drinking to coffee has been quite astounding."
A start-up founded on a gentleman's handshake dealt Leon Lau his biggest business lesson.
"I don't have any standout regrets but, if pushed, it would be an experience that is a lesson for all people starting up a business with a partner or partners," Lau says.
The executive chairman of Asia Pacific IT&T recruitment giant Peoplebank Group began his business in the early 1990s. It was a 50/50 partnership with a friend.
By the late '90s the two partners had differing views on the direction the company should go, which led to a "stalemate at the top", leading to a dysfunctional company "going nowhere".
"Our mistake was no shareholders agreement was put in place and everything was done on a handshake.
"Factions within the company evolved and it broke out into 'open warfare', almost crippling the company and losing the company two to three years' growth," Lau says.
Lawyers and litigation eventually resolved the matter and a shareholders' agreement was signed.
"An exit mechanism was included in the agreement and I bought out my partner. Lesson learnt 'get important matters documented'."
- Sydney Morning Herald