If Gaffer's Buggy is completed before Paige's House, Odd Gaffer will put up his sign by himself, and hurt his back in the process. This will greatly reduce the stock of items he sells. If Paige's House is completed before Gaffer's Buggy, then Pike will help Odd Gaffer put up the sign, preventing him from hurting his back, resulting in significantly more items being sold at his shop.