Krishna described his higher nature (para-prakruti) which is the life-element beyond the three gunas. His lower nature (apara-prakruti) consists of eight elements viz. fire, earth, water, air, space, mind, intellect and ahankaar which is under the hypnotic spell of the gunas. While the former (higher nature) is referred to as the un-manifested which is eternal, indestructible and immeasurable, the latter (lower nature) as manifested which is limited in many ways.
For easy understanding, man can be taken as manifested and paramatma as un-manifested which is beyond senses. The first level of interaction is between man and man which is the result of our identification with the manifested; the next level being between man and paramatma . At the man to man level, things and resources are scarce like water in a puddle whereas it's like the ocean at paramatma's level. The mind which is trained to compare keeps constantly comparing what we have and what others have in terms of material possessions, power and positions which leads to 'grabbing' as everyone fights for these limited things. For example, there is only one post of Chief Executive Officer (CEO) or Chief Minister (CM) but there are always many contenders, contending/aspiring for the same. Every walk of life involves similar situations.
At this level, things are polar and one keeps swinging between the polarities of pleasure/win and pain/loss. Ahankaar gets inflated with victory and the blame games start with a loss. Similarly, one is under the illusion that he is kartha (doer) leading to fear and anger when things don't go their way.
Krishna terms participants of such interactions as perpetrators of evil, misguided fools who follow the path of demons (7.15). An 'evil' who wants to grab would invariably meet another 'evil' resulting in misery seen around us.