He smashed his little castle only to drag his shoe over and use it to build another one. That castle represented everything Greed was. When something was taken or didn't work, he jumped back up and tried again---sometimes with new tools. It wasn't in his makeup to give up.
He sighed again, his shoulders slumping a little. "I know, but I don't want to be second." Funny how skewed his mentality was when Zoe had said the same of him and Lust. What Zoe didn't get was that around Lust Greed fed off of her and it wasn't something he could control. When Greed was around Lust, he wanted Lust. But when he broke away, like he had many times before he wanted other things. In the end he made messes and he went right back to her. Not for sex always, but because Lust was the excesses ring leader. She took care of them. She was their mother as much as sister.
"I kinda scared off her last date," he said in a squeaky voice. "But this new guy," he wagged a finger, "she's dated him before and from what I know of all her exes---they sucked. He steps outta line once I'm busting a cap up his ass." He was protective of his things.