I have very long hair and went in to have some simple layers cut in... I left with half of my hair cut to 3 inches long! I had to get $300 worth of hair extensions put in to fix it! It will take years for it to grow back.
I cried as soon as I left the salon - I work in TV industry and I have shown my hair to 3 top celebrity hairdressers who have all said it's the worst haircut they've ever seen!