1. what makes us, "US" is our 'pattern' or geometric arrangement in space-time. this is described as our desires, memories, abilities, inherent personality etc.
2. love is the combo of the two more basic emotions of "joy" and "acceptance"
3. these emotions are caused to happen together, when one comes into contact with another "pattern" or "geometry" that meshes better than most other patterns with our own "pattern". this can apply to anything from food, an activity, an idea, or even a person.
4. Love is when we come across someone (or something) that matches so well with our desires, dreams, self (our 'pattern'), that we are deeply moved towards 'accepting' this thing that brings us 'joy'. This is why love probably follows and never precedes 'letting your guard down'. One must let their guard down, to truly be 'accepting' something...