One of my friends with the absolute definition of mousy brownish hair had had blonde highlights done professionally every few months for almost all of her life.
But we were in college, and bored one night, and she didn’t feel like going to the hairstylist, and she came up with the brilliant plan to dye her hair black. Unfortunately, our lives did not get more exciting over the next two days while we thought through the plan and eventually we were dying her hair jet black. It actually worked pretty well - we were able to keep most of the dye on her hair and off her skin and clothes. In fact, the hair looked great when we were done.
Problem was, was that she was very pale, and she looked like a goth. Not that there’s anything wrong with that, but she wasn’t one. It was simply too dramatic a change for her, and she wanted to die it back - in fact, she wanted to become a pure blonde.
Common sense would tell anyone that that wasn’t about to work, and her friends were not bereft of common sense. Sadly, she didn’t have that, so she came by a few days later with a box of hair stripper and a few boxes of blonde dye. We tried to convince her that the best she could possibly get was brown, her original brown color, that was a possibility - blonde was not going to happen. But she didn’t believe us, and insisted we try.
So, we put on the color stripper, but unlike the original dye it was hard to tell whether it covered her hair completely and then trying to get it even was impossible. But we tried, really honestly, we did. And let it sit for the appropriate amount of time. It didn’t work. Her hair ended up anywhere from transparent to orange to a few tips and ends and roots of black here and there where the color stripper just didn’t make it. It also had the texture of hay. It was awful. She looked at it in the mirror, and then insisted that we put the blonde dye in, and was certain that that would fix it. We again tried to push brown on her, because that was the only shot - but no, she wanted blonde.
So, we did blonde, not once, but twice at her insistence. By the end, there were a few over peroxided places that actually did look blonde, but mostly a multitude of ghastly, not found in nature oranges and those same tufts of black that never quite got redyed.
She wore hats for a week. And then finally went to her old hairstylist who put in the exact brown we had tried so hard to convince her to try.