1. Remove walls
  2. Remove floors and replace.
  3. Gut the kitchen, and replace with all new stainless appliances.
  4. Gut the master bath, and replace with stone and tile.
  5. Never touch the garage.
  6. Landscape the yard, and build a deck ever other show.
  7. Run into mold, plumbing problems, or need to add a support beam.
  8. Come close to being over budget every time.