In the current real life, systems theory is an abstract background of systems thinking, which is a part of systemic behavior. The systemic behavior is the alternative to the currently prevailing one-sidedness that puts all of humankind in danger of self-destruction due to the crucial over-sights (all the way to world wars) that unavoidably result from the current over-specialization (along with crucial, but partial insights), if the specialists fail to practice creative interdisciplinary cooperation. This contribution is a next phase of research after the contributions by Matjaz̆ Mulej, Zdenka Z̆enko and Viktor Z̆akelj (2017) and by Matjaz̆ Mulej, et al. (2013). Although the abstract background and thinking that the systemic behavior applies, are very necessary, theory and thinking are no longer enough for systems science to be a relevant science and practice helping humankind find the way out from the current blind alley and survive as a healthy civilization with a healthy social and natural environment. The suggestion in this contribution therefore reads: Let us systems and cybernetics scientists make/enable the transition to systemic behavior, which applies all the many theories, which are components in the background of systemic behavior in practice, next to each other and/or in synergy. Analysis, i.e., studying per isolated parts is too overlooking and one-sided to be enough. So is teaching on a single one out of several systems theories. Reality is too complex. Teaching is a part of this necessary effort, which must lead to a global peace and survival of humankind of today instead of the current hating the human descendants.