1. Don't show your emotions, especially if you get angry or upset with your employees. I had a boss who sent me an email asking, "Can you explain to me why you didn't do this?" after I neglected to change a status in our sales app for a customer. Treating an employee with contempt does nothing for their morale, and will probably make them resent you.
2. Don't bad-mouth your employees, especially in writing. I worked for two guys who acted like Beavis & Butthead: they fucked off and giggled like two little girls all day long, harassed and intimidated their employees, sent emails between themselves disparaging the employees and talking about all the drugs they'd been doing.
3. Don't make stupid bigoted comments about sex, race, religion, sexual orientation, weight, etc. I've had a couple of bosses who asked me to "do a friend a favor" or what they should serve for breakfast at a morning meeting because "being a woman" I would know about what to serve for breakfast.
4. Don't let your insecurities (or other mental illnesses) get in your way. A woman I used to work for always told everyone she had a degree in Communications (the degree people get when they can't hack an English Literature degree), but couldn't spell potato and did everything in her power to fire me after I teased her about it. Guess what, Barbie doll: you look like a moron when you try to make yourself look smart by bringing up your degree but can't spell or use "big" words properly.
5. For God's sakes, do not micromanage! I used to work for a CIO who couldn't tie his shoes, much less manage anyone. This imbecile claimed it only took "five clicks" to troubleshoot and fix PC problems, mainly because he wanted to outsource our PC techs to India. If we experienced an outage or problem, he had to be right in the middle of everything, telling us what to do and how to do it. Consequently, it always took twice as long to fix anything because he didn't know his ass from his elbow and his meddling only inhibited the actual problem solving.
The best bosses I've had simply get the hell out of the way, lead by example, and offer guidance when necessary.
