Shark Tank is a business-centered television show featuring start-up entrepreneurs who pitch their ideas to “sharks,” millionaire entrepreneurs, who invest in companies they find to have potential. When more than one shark is interested in a product, they will fight to get a piece of the action, causing eruptions in the tank. However, if a shark dislikes a product, they're not afraid to express that aversion, while the entrepreneurs dread hearing the infamous words, "I'm out."

Since the first episode aired in 2009 on ABC, "Shark Tank" has gained tremendous popularity among audiences. Of course, being an entertainment television show, everything on "Shark Tank" is exaggerated to be more exciting for viewers. However, all the sharks are real life successful and dedicated entrepreneurs. There is something to be learned from each shark, including some of the guest sharks who have appeared throughout the course of the show.

1. Kevin O'Leary

When Kevin O’Leary was only 28 years old, he founded SoftKey, an educational software system, which he later sold to Mattel for $4 billion. Nicknamed “Mr. Wonderful,” Kevin has taught us that money is everything. In fact, this is such an important concept of his, that I am going to repeat it again. Money is everything. Kevin is so obsessed with making money that he will rarely offer a deal in the tank that doesn’t involve a royalty for himself. He taught us that you can have all the passion in the world, but if you don’t have a plan to make money, you’ll never get anywhere. Kevin also speaks frequently on “Mad Money,” so if you are ever in need of investing advice, tune into CNBC for advice from Mr. Wonderful.

P.S. Never invest in a company that doesn’t pay dividends!

2. Lori Greiner

As the friendliest shark in the tank, Lori taught us that a smile goes a long way. Often times, she makes a better business partner than the other sharks due to her ability to connect with the entrepreneurs. Lori also holds the advantage of being the "Queen of QVC," and owns 120 patents and 500 products. In Season 4, she invested in "Shark Tank’s" best selling product, Sponge Daddy, which has grossed more than $50 million in sales since its premiere on television.

3. Robert Herjavec

Robert is a Canadian businessman who got his start by creating an internet security software after being fired from his previous job. Robert is one of the more easygoing sharks in the tank, but isn't afraid to get serious to prove a point. Since the start of "Shark Tank," Robert has invested in several successful companies including: Tipsy Elves, Chord Buddy, Breathometer and Revolights. Robert taught us the importance of marketing -- customers will not come to you. Small companies, in particular, need to focus on self-promotion in order to become successful.

Fun Fact: Robert performed on Season 20 of "Dancing With The Stars."

4. Daymond John

Growing up in Queens, Daymond was inspired to start his first clothing company, FUBU, at the age of 25. As “The People’s Shark,” Daymond enjoys connecting with his fans and constantly provides opportunities to meet with them. Daymond recently published his book “The Power of Broke,” which teaches aspiring entrepreneurs how to turn their biggest weaknesses into their greatest strengths. Throughout the series of "Shark Tank," we learned the importance of timing from Daymond. When he’s interested in a deal, he will sit back while the other sharks talk. When the timing is right, he sneaks in with a slightly better offer to steal the deal.

5. Barbara Corcoran

Barbara began as a waitress in Manhattan, until she received a thousand dollar loan and turned it into a business that she eventually sold for more than $60 million. From Barbara, we learned to never be afraid to quit something you’re unhappy with. By the time Barbara was 23 years old, she had tried 20 jobs, none of which suited her, until she finally became her own boss for the Corcoran Group. We also learned to never give up on the things we want the most. Barbara wanted children, but unable to be conceived herself, had to undergo a fertilization process. This took years and cost tens of thousands of dollars for each child. By the time she got her children, she was older than the average mom of children the same age as hers, but despite this, she is still the most enthusiastic one, who genuinely appreciates the company of her children.

6. Mark Cuban

Mark Cuban is undoubtedly the fiercest shark in the tank. He is the outspoken owner of the Dallas Mavericks, Landmark Theatres and Magnolia Pictures with a net worth of more than $3 billion. Mark got his start in business at the age of 12 selling trash bags door to door, in an attempt to earn enough money to buy the pair of sneakers he wanted. He taught us how to get off our behinds and work for what we want, because the American Dream is alive and well. Mark also taught us how to call out BS on the spot -- he is not afraid to speak his mind and because of it, people respect him more. Though he is one of the hardest sharks to strike a deal with, Mark is one of the best investors to have by your side.

Guest Sharks:

Throughout the series, "Shark Tank" has featured some famous guest sharks, in which we can take away a great deal of knowledge from.

7. Nick Woodman

Founder of GoPro, this young entrepreneur was featured on "Shark Tank" for the finale of Season 6. In his short time in the tank, Nick taught us the importance a product name has on marketing. When Nick was founding GoPro, he originally intended for the camera to be used specifically as a surfing camera, and luckily didn't name the product SurfCam. If he had, the product wouldn't have appealed to as wide of an audience, and likely would not have become the success that GoPro is today.

8. Chris Sacca

Chris Sacca proved to be a great edition to the cast in his appearance in Season 7 of "Shark Tank." From his short time with us, we learned to not be afraid to take risks. Chris was head of special initiatives for Google when he left to become a proprietor of Lowercase Capital. He also took risks when he invested in the early stages of Twitter, Instagram and Uber -- all of which turned out to be major successes.

9. Ashton Kutcher

Though it may be hard to imagine “Kelso” as an investor, Ashton has actually become a very successful businessman since his acting days. In 2010, he founded a venture fund called A-Grade Investments, which made investments in Spotify, Soundcloud, Uber and Path. With his appearance on "Shark Tank," Ashton taught us to not be afraid to branch out your areas of interest -- he is one of the highest paid actors on television, yet Ashton still made the decision to become an investor. At one point in the tank, Ashton even cut off Mr. Wonderful to say, “You’re belittling people, and that’s not OK!” Though only in the tank for a short amount of time, Ashton was able to reach out to a new side of his fans, and prove that you can be successful in many areas.

While "Shark Tank" is a television series providing entertainment, there is also much on the business side to learn from each shark. Season 8 begins on September 23 at 9|8c, so prepare yourself for the best season yet! And if you can’t wait until then for more "Shark Tank," catch ABC’s "Beyond the Tank" series, where you can get a sneak peek at companies behind the scenes after their debuts on "Shark Tank."