Your friends can help you decrease the waiting time for your buildings or help you collect profit from them when visiting your city. However, there are some exceptions. Here is the list of buildings that cannot receive any help from neighbors:

  • Aqua Park
  • Astrologer's Home
  • Australian Opera House
  • Cargo Port
  • Christmas Tree
  • Club or Super Club
  • College
  • Concert Hall
  • Fairy Light Christmas Tree
  • Film Set
  • Furniture Factory
  • Hawaiian Restaurant
  • Jet Ski
  • Keepers Hut
  • Love Reality Show
  • Ski Resort
  • Sports Village
  • Stadium or Super Stadium
  • Surf Station
  • Tailor's Workshop
  • Tennis Court
  • University
  • Volleyball Court
  • Water Park
  • Wedding Palace
  • Yacht
(This list may be incomplete)

Neighbors CAN'T speed up the main buildings in the Bay: 
Captain's House
Maitre D's
Belvedere
Hotel
Workshop
Restaurant
Do-Do Nest
Pool
Spa
Ship
Tropical Garden Patches
Bridge
Cliffedge Lighthouse
Tourists
Caribbean Square
house "figueres" 
(More may be added at the Bay grows)