Economists spend a lot of time discussing the conflict between actions that serve an individual and actions that serve the community. (The Invisible Hand refers to actions that directly serve the individual and indirectly serve society.)
Take water use, for example. People who use more than their "fair share" serve themselves while leaving less for everyone else. If others respond by increasing their use, then shortages grow worse. If they respond by attacking the "wasteful" individual, then conflict can erupt that's even more costly.
One solution -- my preferred solution -- is to allow people to use as much as they want but charge them for the privilege. As prices rise, everyone will use less, and shortage will not result. That's what happened when gas prices rose -- everyone faced the choice of using less or paying more, and everyone was happy with their action. Some people may have been upset at others who continued to drive SUVs around, but they know that those drivers were paying a lot to be wasteful, which was (often) an acceptable punishment for such "anti-social" behavior.
That case with water could be the same, if we raised prices, but there are many barriers -- cultural and political -- to doing so. Without prices, there are fewer options on the table. Most places ask people to use less; some of them regulate use. Both of these schemes will fail if people set themselves above the community. (For example, regulating lawn sprinklers is useless if people water at night, take long showers, or water their back yards.) That's been the case in most parts of the US, where individual rights are often stronger than the sense of community. (There are some exceptions, and they often surface when a critical mass of citizens, media and leaders come together, agreeing to do something.)
In other places (Australia, as I am learning), people are willing to use less, because they have a stronger sense of community, and doing the right thing. That force appears to have been the primary driver behind Brisbane's drop in per capita use to 140 lcd, and Melbourne's current use of 174 lcd (46 gcd).
I am sure that readers can give their own examples of conservation successes and failures that can be attributed to a strong or weak sense of community, respectively.
Ironically, it is hard to built "community" in an area (gated communities, anyone?), but a community, once built, lowers the cost of almost every activity in life -- education, safety, traffic, resource use, and so on.
Bottom Line: There are many ways to motivate people; choose the right one for the job.