We live in an age of high frequency trading with those sophisticated algorithms that are able to profit upon small inefficiencies in the consistency of market prices, as well as to take advantage of "seeing" block trades that are about to occur so as to take a very small fraction of profit off of that upcoming action, that know the inestimable value of being a few milliseconds faster than the other traders when it comes to buying and selling, and are able to trade quickly upon actionable news whether discovered serendipitously or by some other means. The stock market, today, with its very low trading costs, is a volume game, and high volume is very, very good for brokerages, in addition to the fact, that nearly every trade has an opportunity for someone to get over on somebody else.
All of this that is going on, is really, in effect, by virtually all of the players in the stock market, fundamentally a bastardization of what the stock market is supposed to provide, which is, in a nutshell, the investment of dollars by outside investors into public companies so that these companies can raise needed capital and thereby be able to hire the employees , buy the materials and to create the infrastructure necessary to grow and to run their business; in which a public stock market's main function is to provide an open exchange that will facilitate the buying and selling of those securities so that those that invest in these securities have a means to trade in and out of such, that provides liquidity as well as the confidence that their investment dollars are safe, and that have a secure value based upon the worth and profitability of said corporation.
While that is the way it should be, the days of the buy and hold investor seems to be the bygone days, replaced instead, by all sorts of players, trying to make that quick money, in whatever means that they find attractive for their strategy, or if not exactly that, replaced by those, that don't really care how things work, or know much about the companies that they do buy stock in, but only really care about their investment making them money, by whatever means that may be. The problem with that type of group mindset, is that when investors aren't really investing for the long term, and don’t even know what they are invested into, than they really aren't in it for the long haul; what they are really in it for is to make money, at least on paper, by trading back and forth, hoping that they get out, just in time, for when the music stops, and there does come a time when the music does stop, the drop might just be catastrophic, because too many investors typically don't have a clue about the intrinsic value of what they are investing in, instead, all they have a clue about is that this price is higher than that price.
Ideally, a stock market is created, so that those that have capital, that is, money, can help society to grow and advance, by investing their money into worthy companies, so that the GDP of that country increases, as well as providing needful employment opportunities, so that the proper circulation as well as the proper investment of monies into companies of merit and worth is definitely beneficial for society; whereas, the mal-investment of those monies is not; and when those that are investing their savings into a stock market, do so without understanding the correct purpose of such, they are actually aiding and abetting the destabilization of markets, which inevitably leads to booms and busts.