“You cannot be what you cannot see.” I don’t totally agree. Sure, it’s easier to become something that you can see or have experienced before, but I think you can create something that you haven’t seen, you can create a career path, or a passion project, or a way of thinking. Some people are wired that way. They are not limited by what is and can conceive of what previously has not been possible.
But, when it comes to love and generosity we cannot express what we have not received. If you have never been fully loved, or if you have never been on the receiving end of an act of generosity, you will not be able to love from a healthy place, or to be generous. Not fully anyway. You might be able to manufacture something that looks like it but it will be a poor imitation and will not last the test of time.
Maybe that is why some people in your life don’t seem to be able to express love or gratitude in a way that you think they should. Your love and generosity towards them could be the thing they need so they can learn it and then begin to act it out.