a bad hair day Meaning If youre having a bad hair day, everything seems to be going wrong for you. For example Poor Sues in a terrible mood. I think shes having a bad hair day. I knew it was going to be a bad hair day when my car wouldnt start. ━━━━━━━━━━━━━ #Idiom_of_the_Day @EnglishoftheDay @QuizoftheDay 7.4K views08:29