Most of us in the States cannot live without our cell phones now days.
The same is definitely true in Japan.
The only difference is that people absolutely love decorating their phones there.
I have some cell phones with decorations here in the US but the ones in Japan are way busier!
A lot of Japanese girls love their cell phones to have rhinestones and flowers. There are shops where they specialize in decorating cell phones.
Some people have too much decoration and the cell phone itself looks smaller.
I guess you can never lose your cell phone this way then ;)