Incomprehensible turnover. In this one-employee company, there have been six or so salespeople and six or so analysts come and go in the past few years. Management claims it's because his hires have had no integrity, but the truth is, they just couldn't stand working for management.
Extraordinary micromanaging. For example, management will make you re-write things endlessly, only to eventually say that the way you had it the first time is best. Then he'll say that writing is an iterative process. The truth is, management is too detached from your project to really understand what you're writing about, and is obsessed with sounding more clever than necessary. There are a lot of other examples I could give, but you get the picture.
Zero true room for advancement. Management will tell you all about the amazing career path you're on, working tirelessly to make him rich. It's all a lie. No one advances beyond associate here. Ask around. Do your research before accepting a position.
Insufferable management. Long hours, underwhelming pay, micromanagement, etc. - this stuff is all completely tolerable if you really like the person or people you're working for. Unfortunately, this is not ever going to be the case at this company. Management treats employees like dogs, except when they're trying to manipulate the employees into liking management, which is always transparent and always nauseating.
Last but not least, consider this. The company has one full-time, non-owner employee. One. ONE. Yet there are 18 positive reviews posted for this company. This is because management went berserk after a couple of former employees wrote honest, negative reviews after leaving the disastrous company (two of which remain posted as of this writing). Management responded by calling them "FAKE REVIEWS" and then slandering the writers. They're not fake reviews. I worked with the people who wrote them. As for the 18 positive reviews? Doesn't seem to pass the smell test, given that there's only one full-time employee at the company. If that's not enough to scare you away, then you deserve to work for this company for a while.