In regards to overages it's a matter of discipline and buying the service level that meets your needs.
Agreed.
You have to be a little responsible. Some people will have legitimate needs for a lot of data, but a lot of us could reduce data usage by not updating apps via cellular data and so on. If you have children, teaching them to be a little responsible could save a bunch of money by not overpaying for data they don't need. And a lot of the overages aren't that bad. For example, AT&T does $15 per GB for each GB you go over. If you go over once or twice over a span of a couple of months, it would probably still be cheaper than overpaying for data you didn't use.