1. The staff has developed guidelines for dealing with you and quietly passes them to new employees. "Never suggest that there might be another way of doing something," they might say. Or "Act self-deprecating so he doesn't feel threatened."
2. You have one or two fanatical acolytes. Yes, such devotion may be a testament to your fabulousness. But often when a boss is perceived as universally loathed, the staff opportunist offers herself up as sole confidante and friend, seeking power and favor at the expense of more honest, critical employees.
3. You never see people walk by. Employees would rather circumnavigate the entire office to get to the coffee machine or bathroom than take the shortcut past your door and risk being invited in.
4. Your 360-degree evaluations come back short and full of generically positive comments, with one very mild criticism ("Sometimes she works too [bleep] hard for her own good") thrown in for credibility's sake.
5. People don't volunteer for your pet projects. The idea sucks, and they're afraid to tell you, or it's brilliant, but the consequences for letting you down are too terrible to imagine. And, of course, if it's your pet project, you'll probably work on it as well. Which means more time spent...gulp...with you.
6. You have legions of former employees, but they rarely give your name as a reference for new jobs. Either they don't trust you to give them their due, or they worry that because they were so miserable working for you, your recollections will also be dismal.
7. You have legions of former employees, period. If your staff falls away like linty Post-it notes, ask yourself: Is high turnover the problem? Or am I?