Hello Kitty turns 50 on Friday. Befitting a pop icon at midlife, the bubble-headed, bow-wearing character's fictional birthday has brought museum exhibits, a theme park spectacle and a national tour.

I first met Hello Kitty through a friend of hers named Pompompurin. I was about six years old when one of my mother’s coworkers gave me a pen featuring the bright yellow golden retriever and a small ...