It has happened to the best of us. We want to make a change, we feel excited about what we plan on doing, and we then leave the fate of our hair in the seemingly capable hands of a professional. There are many reasons for color to turn out awry; you had a vision, the stylist had a separate vision, you had pre-existing color on your hair that effected the way that the new color processed, your hair has it's own personality that does or doesn't accept the new pigments, the lists goes on... A little bit about color: a strand of hair has a central cortex and then layers surrounding that cortex. With permanent color, the color penetrates into the cortex, changing the inner-structure of the hair (box color from the store is especially harsh on the cortex of the hair), semi-permanent color is deposited under the layers of the outter-cortex, it doesn't change the inner-structure, but it can soften the outer-structure of the hair (this is desireable for graying hair that needs to be blended smoothly).  The following list is not full-proof, but it is the best way, we found, to avoid situations where you are left devastated by color How to Avoid Bad Haircolor

• Be specific - bring in pictures to clarify, words can only explain so much.
• Be realistic - we can do our best to move mountains for you, but at the end of the day, we can only do so much and you will still leave looking like yourself, no matter what. 
• Be honest - don't be afraid that your stylist will be mad if you went to another salon for color or used box color at home, they will be grateful to know all of the information so that they don't end up scratching their heads wondering why "virgin" hair didn't lift like it was supposed to (virgin hair, by the way, is hair that has NEVER been color-treated. It doesn't matter how long ago you put color on your hair, unless you chopped off that hair, it has previously been color-treated.
• Do your research - with the rise in social media, most salons are vying for an online presence which means most credible salons will have pictures of their work for you to see for yourself. 
• Be compassionate - if it does happen that the color comes out wrong, understand that, that stylist is probably just as devastated as you are, if the situation calls for it, and if they seem truly committed to fixing it, let them - they will know better than another stylist how your hair reacts now. However, sometimes you just gotta cut you loses and come to us ;) 

Check out the video of Emily Rexford doing a color correction on a charming girl who went somewhere else and did not get what she wanted...