Our culture has the attitude that complaining is a waste of time. The idea is that complaining about something (like not making enough money) will not change the thing itself, so you would be better served by actually doing something about the problem.
This relies on a very simplistic view of human nature. It ignores the fact that people think and feel before they act. Sure, if you throw an apple at someone's head, they are going to duck without thinking. But most of the decisions we make throughout the day are premeditated, and as such, whether or not we will do something depends largely on what we think, or feel, about doing that thing.
Complaining is just one way of thinking about our feelings toward something. The same people who would discourage you from complaining would not discourage you from making a 5-year plan, yet these are the similar activities. Both involve thinking through something before actually doing it. And I, for one, am glad people complain. If everybody just went out and fixed the problems they complain about, crime would shoot through the roof.
Of course, complaining does consist of negative energy, and doing it too often can become a substitute for necessary action. But far more often than not, complaining is a way for us to discharge some of our frustration and aggression toward something, so that we can return to the same situation with a little more calm.
Finally, it's also a way for us to articulate what matters to us. If we find ourselves complaining about our lack of money time and time again, then after a while we can be sure that making more money is something important. Now let's talk about how to get there.