Do we invest in people's lives consciously, or unconsciously, hoping for something in return?
In return for support, comfort, promotion, favor, loyalty, good will?
Do we ever subconsciously think, "So-and-so owes me (any of the above) because I did this-or-that for her?"
If that is the case, those acts of kindness we do are truly "investments” into human bank accounts as we seek a "return" of some kind no matter how big or small. Pay back is expected or anticipated.
If we pour ourselves into people simply because Christ’s love compels us to meet a need (either emotionally, physically, financially, or even spiritually by offering godly counsel);
If we give of ourselves freely to those who may eventually betray us, to those who have no power to reciprocate;
If we bestow acts of kindness into people truly without any hope or thought of "return" (not even a "thank you"), we go against worldly wisdom truly becoming conduits of God's abundant grace.