Freedom.
Lucifer erupted from the Cage in a visceral moment of light and ecstasy. He spilled out into the warm night, flushed the windows and archways of the small church with light, his Grace eradicating any indication that demons had lain dead on the floor before. He felt the world around him, could not completely ignore the dissatisfaction of finding smog and pollution and hate and sin, but was too happy to let it ruin his joy, too exultant at the world itself, rendered from God. He gave the Grace equivalent of laughter, bright and exhilarated.
At his shoulder he then felt a familiar presence, a humble joy, small, self-effacing. It shocked him, that his Father had taken on so small a form, but before he could mention it, the voice rang light and delighted in his Grace, "I took the liberty of placing Sam and Dean out of the blast radius. I don't think Sam is quite ready to meet you yet." And it was so full of mirth that Lucifer was caught in the quiet gaiety his Father filled him with and could not argue.
They parted ways, soon after, for his Father wanted to 'play around a bit' before they met again, and Lucifer had to find a vessel other than Sam in the meantime. After the initial euphoria had passed, he recognized that Sam would indeed be very hard to convince of his peace - a thousand years worth of 'bad rap' as his Father had almost gleefully explained was not likely to be changed in a night, especially when Sam was in a state of shock as he likely was now.
That was perfectly acceptable to Lucifer. His patience could not be tried when he felt such absent-minded and full joy.
He did not yet, but he was ready to love humans.
