A loser's term of jealousy for a nice house he or she can never afford.
"Did you hear how well Susie's doing? You know we used to all make fun of her in school, well I hear she's got a good job and just bought a beautiful new home."
"Yeah, she's just the type who'd buy a McMansion. I'm happy with my double-wide in the trailer park, it's more 'real.'"