Hair color isn't always about just "color". It's about shades, hues, and a good cut that will show off your new color. Perfect color doesn't come in a bottle. If you are hoping to get a color correction for past mistakes (caused either by you or another salon), it will take a real expert to add in the right toners to counter the faulty shades you are trying to get rid of.
But any such stigma associated with coloring our mane is long gone. Anymore it's so common no one gives it a second thought. In fact some of us would be hard pressed to recognize our own natural hair color it's been so long since we have seen it. Because as they say color is a girl's best friend.