Thou Shalt Manipulate
You're a master manipulator. You know how to answer the phone when your boss calls and when your mom calls. You know the right pitch and tone of your voice, the right greeting, and exactly what to say.
You do the same thing when you dress up; you're saying "Listen to me, I'm important." Whether or not you herald any actual importance, you've adopted the uniform of power. The opposite is also true--dress down, bum it for the weekend, and see how much attention you garner.
We do this all the time. Think you're immune? Do you dress up for interviews? weddings? dates? Yeah.
I'm not pronouncing an indictment of your clothing choice, rather your motives. Manipulation gets a bad rap because it usually carries the negative connotation of devious intentions, but it simply means "to effect change in a desired direction." I can manipulate my shoe laces into a bow; nothing sinister about that.
The point is to (1) be aware of your motives and (2) be good at it.
That is to say: Effect change within yourself to give yourself the best possible advantage (this can be as simple as wardrobe or as complex as your attitude) and do it effectively. Don't half-ass your appearance; you're only going to shortchange yourself.