Financial Crisis, what is it?

The most recent financial crisis had set me thinking on how the stock market crashed. Curiosity aroused in me. Why, I thought, the money was still circulating around the sellers and the buyers would in the end have to sell it away, and gain back the money, that's if they manage to sell it away. This post I am writing on is for novices who wants to know how the stock market crash.
At the start, you may think that the money was still circulating around the buyers and thus there would be no way the stock market could ever crash. But think about it, if you are an investor, you would surely want to gain profit from your shares that you sell right? So this is where the problem comes in. People felt that buying shares was the easiest way to earn money, and the economy bloomed. It was then the people started to feel greedy and wanted more than what they had before. Take for example a scenario: Investor A bought an item from a seller at a price of $1, and sold it off at a price of $1.20, earning him a profit of 20cents. Investor B then buys from Investor A, knowing that he is able to earn a profit if he buys from Investor A, and he sells it off to Investor C, at another profit of 20cents. This trend then goes on all the way until the price of that share itself is so high that no one wants to buy it anymore. So much of the shares is circulating around in the market, why should anyone want to buy it at such a high price? When unable to sell it off, the investor would start to consider selling it off at the price that he has bought it for, which makes him unable to earn a profit. When no one wants to buy it at the decreased price, investors start to consider a loss, as long as they get back their money. This is when the share price starts to plummet, and the stock market crashes.
I will try to update this post ASAP when I get more information regarding this matter. I am not naive, I am curious on this matter. Post me a comment if you find out anything that needs to be added or any wrong information. Thanks!~