Which hand do you use?

While taking a shower yesterday I poured shampoo into my left hand before smearing it into my hair. For a second I didn't know what to do with it. I hadn't realized before that moment that since day one I had been holding the shampoo bottle in my left hand and pouring the shampoo into the palm of my right hand. I stood there for a second while my brain adjusted itself to the new configuration. My body had been so conditioned to applying shampoo to my scalp with my right hand that when I attempted to do it with my left it was like I was performing the task backwards. I got through it but a shower is supposed to be a serene activity not one of such shock.