It is an act of financial recklessness that can leads an individuals to spend more then they earns, and potentially causing debt or financial difficulties. I strongly believe that our needs and wants are much greater than our income, but the best way to prevent overspending is through budgeting, just as everyone said.
You can say someone is being financially reckless when spending way more than he earns and like you noted, leading to financial difficulties and certainly debts.
Budgeting in simple terms means planning whatever income you're got on how best to spend on what's important and needed at the moment. Our wants being so insatiable could be said to be greater than our income, our needs however, can be comfortably taken care of also having some left over for savings.