Tiling Flooring, Big Or Small Squares,how To Make A Room Seem Larger?

Smaller tile makes the room feel larger

I thought that smaller tiles would make the room look bigger too, so I went with smaller tiles, (6"), in both my bathrooms. They made the room appear smaller and busy looking because of all the grout lines. I tore it out later on and replaced it with 12"x12" and it makes the floor space look larger.
  Have 287 square feet between kitchen and diningroom. Layed 18 inch tile. The room looks more open and the lines are cleaner looking.