Tax system operation and efficiency, resulting in the quantity and quality of public goods provided, the level of tax revenue collection and modeling strategies for fiscal behaviour of taxpayers, are fundamental elements of sustainable economic, social and cultural each state. Concerns authorities were directed specifically to structural changes in tax systems, adaptive process of globalization, regional tax competition to attract capital and increase tax revenues and less on modeling aspects fiscal behaviour of taxpayers. The importance of these aspects of modelling positive behaviour should more concerned governments and scientific community for better regulation of the interaction that is created between tax authorities and taxpayers, to identify and implement strategies for interaction aimed simultaneously at least two aspects, respectively: -based interaction progressive transition from command-control excessive punishment for interaction with emphasis on supporting and advising taxpayers; -increasing taxpayers education. Behavioural resetting the tax authorities and the taxpayers, leading to shape fiscal behaviour and strengthening interaction strategies based on counseling and education will require an intensive educational effort and, above all, for a long time. These situations are specific to countries in transition from a centralized system t a democratic one, as is the case in Romania and Moldova, where there are some delays in adapting to the new democratic system, that have democratic rights and duties means having. You can acquire some positive developments fiscal side, behavioral, democratization and transformation of long-term only as long as taxpayers comply with and be subject to the tax law. During adaptation to the new fiscal reality, tax systems in these countries will not generate enough revenue.