I radiate love from within.

There's someone behind a post office counter who treats the polite customers and the rude ones with the same unbothered warmth. It isn't a technique. It doesn't depend on the queue behaving.

The source isn't the other person. Warmth generated by how nicely you were treated this morning runs out around eleven and can be switched off by one bad exchange.

What people describe as loveliness in someone is nearly always this: attention that doesn't require anything back. It costs less than it appears to, and it alters the temperature of a room within seconds of arriving in it.