There are many situations in life, in which you might find yourself as the leader, the general, the director, the manger of a certain person or a group of people. Now, when this happens (and I'm sure you are all quite successful, so please, remember this bit), please harken your mind back to the days when you were not the boss, you were the peon, the direction-taker, the underling, the intern, and act accordingly.
Just because you have been given the reigns does not mean you can suddenly treat fully grown adults as if they were your unruly kindergarten class of children, nor your proverbial punching bags for your aggression or your superiority complexes. Not only does it make you look small and weak and the opposite of commanding, it makes those inferior to your position hate you, and when they hate you, you will lose. Every time.
Of course you cannot be everyone's friend, therapist, and guide, but there is such a thing as commanding with grace and dignity and you can stand your ground while still respecting someone else. Yelling at everyone to "close your books, stand up, and watch your mouth" or to "get the $%*K out and do your g*%#%&m job" does not engender any respect and it makes you look like a loon, to boot. You want your inferior's respect and admiration, not their insatiable mockery and eye-rolling behind your back.
Also, this tip works equally as well for people in the service industry, just because they provide you with a service, does not mean you are free to treat them like dirt. Remember, someday you, or someone you know, might be a waitress, bartender, stylist, beauty technician, etc and you will not appreciate it when they or you are stepped upon.