I know many of the people on this forum use their bikes for transportation. I love all the extras you can buy at the bike shop. Here are some of my favorites:
my sheepskin bike seat cover
hand grips
Tuff tube and slime to prevent flat tires
A headlight and tail light that I can recharge on my computer (instead of buying batteries)
my lock
my walkydog attachment
When I was a child, I loved my Mickey Mouse bell and the horn that I got for Christmas. Sissy bars and flowered banana seats were big in those days. The kids in our neighborhood rode out bikes everywhere. Nobody wore helmets back then...now I always wear one.
How about you?