Do you think people’s life has been greatly improved by the

No, I don't think so。 Here are some reasons:
Cell phones are convenient but they have some serious drawbacks。 For one thing, they're expensive and require long-term contracts that are just about impossible to break, although we offer a few suggestions in Escape From Cell Phone Purgatory。 You might also consider a prepaid plan。
There are also some hazards associated with cell phones: the batteries can explode, they're a big distraction to drivers and the question of whether they pose a long-term health hazard has not been settled, despite what the industry apologists would have you believe。
Cell phones not only don't work very well -- much of the time they don't work at all。 This is completely normal and is about the best many of us can hope for。 There are three basic reasons:
Too many people have cell phones;
There aren't enough towers to handle all the people who have cell phones;
Most people don't want a cell phone tower in their backyard;
Cell phones use microwave frequencies, which don't travel very far。 Ergo, no tower, no phone。
Anyone who absolutely, positively has to have a working phone at all times should keep this in mind。 It applies not only in rural areas but in the heart of great metropoli as well。 My advice: carry a few quarters with you。