Everything we have does not belong to us. Nothing has any value unless it is shared (or even sold, for the capitalists within us) among us as people. We cannot find a moment happy and not talk about it, because happiness can only be true when you acknowledge it to someone else. If I say to myself: „I am happy!”, I will be lying to myself and feel no emotion. But if I say „I am happy!” to someone that I care about, then my whole soul flourish and I can acknowledge it to myself after that.
All valuable things in life are demanding to be shared, otherwise they will be worthless components of our life. In economy, goods are gaining more value the more they are traded. If no one trades them anymore, demand becomes scarce and goods are to be forgotten.
I think the same way in terms of our hearts. Although physically we are complete, we are truly complete when we give our hearts away, as only then we gain a greater benefit: we gain another instance of ourselves, we get to share all the rest of the important components of our lives, we get to exchange, donate or sell at dumping prices and this makes us the richest persons in the world.
Only by lending our heart to another person, we double everything that we stand for, that we fight for and we become the best version of ourselves. Because, in a world where everybody fights only for himself, TWO can still turn things upside down.