I refuse to own a cell phone. I don't want to be accessible to people whenever and wherever I go.
When I play basketball with my friends, we constantly have to stop so they can answer their cell phones every 20 min. I tell them to turn their phones off for a just a few hours, but they can't do it. I think it's pretty damn rude of them.
I don't talk to my friends, family or my job constantly, and I'm still a fully functioning member of society. If people need to contact me and I'm not home, that's what an answering machine is for.
And I don't feel the need to talk to people on a phone while I'm driving, in the grocery store, in the bank, at school etc. The rest of the world sees no problem with that however.