| Special to USA TODAYHedge funds, short selling, short squeeze, explainedFirst GameStop, then silver. Reddit users are putting hedge funds to the test, one short squeeze at a time. Here’s what you need to know.Just the FAQs, USA TODAYI will go to great lengths to avoid crowds. I have found that they rarely bring out the best in people. Whether myth or not, the notion that lemmings will follow a herd off cliffs — an old Wall Street metaphor — is illustrative. Crowd-think can be destructive.Enter the meme-stock craze, where investors follow tips from celebrities or message-boards, regardless of the underlying fundamentals of the company. A crowd of traders is buying stocks simply because their peers are buying.Take Blackberry (BB), for example. I came across my old Blackberry while cleaning out a junk drawer this past weekend. I am pretty sure the last time I saw it was over 20 years ago. That Blackberry was indispensable to me in the late 1990s and early 2000s, which makes my point. When was the last time you saw one in use? Blackberry is now primarily a software company and no longer makes smartphones. Revenue has been declining for years. A stigma no longer? Companies hire more long-term unemployed.Dry cleaners face crisis: Cleaning services struggle, close amid COVID-19Blackberry stock priceWhy then is the stock up 142% this year? And why have the price movements been volatile? In January of this year alone, the stock went from $6.63 to a high of $25.10 before closing out the month at $14.10. I’d rather take my chances at the craps table.If stocks trade on earnings and earnings growth expectations (as they have for hundreds of years) there is no credible rationale for the moves we have seen in meme-stocks this year. Gamestock stock priceGamestop (GME), the poster child of the memes, is up 1,298% year-to-date, despite a declining business model. But the ultimate speculative head-scratcher is the trading in AMC. The company went to the new issue well once again (for 11.5 million shares) with an announcement on June 2nd that issued a stark warning, no doubt crafted by the company’s lawyers:“We believe that the recent volatility and our current market prices reflect market and trading dynamics unrelated to our underlying business,” it said. . “Under the circumstances, we caution you against investing in our Class A common stock, unless you are prepared to incur the risk of losing all or a substantial portion of your investment.” Yikes.AMC stock priceThe company has registered to issue hundreds of millions of shares over the past seven months. On June 1st, Mudrick Capital purchased 8.5 million newly issued shares from AMC and then turned around on the same day and sold all of them in the open market for a profit. AMC filed the securities documents about the sale before the opening bell, causing the stock price to rise — and Murdick sold. Also, take into account that AMC previously registered to issue shares to be sold directly to the public multiple times before their latest filing; once on April 27th (43 million shares) and prior to that on December 11th (178 million shares).Clearly, the company has a voracious appetite for capital, and maybe for good reason; revenues in 2020 dropped 46% below 2012 revenues. Yes, 2020 was an especially difficult year, but sales were also flat from 2018 and 2019. Still, AMC is up just under 2,600% for the year-to-date. When the narrative doesn’t make sense it is because it doesn’t make sense. Eventually, reality will catch up. This is not to say that some traders won’t make money. They will. But home run streaks eventually end. If you are an investor, resist the temptation to chase these names. Enjoy the singles and doubles in your portfolio. Over the long-term, stocks generate real (after inflation) returns in the high single digits, and nominal returns are closer to 8% to 9%. The rule of 72 reminds us, at that rate, you will double your money every eight to nine years. It reminds me of a story my mother used to read to me, something about a tortoise and a hare. Nancy Tengler is chief investment officer at Laffer Tengler Investments and the author of “The Women’s Guide to Successful Investing.”The views and opinions expressed in this column are the author’s and do not necessarily reflect those of USA TODAY.