When designing your home for you and your family to live in, one thing to remember is how are the areas of my home going to help the daily function of my family.
Other questions to ask yourself are, how is this home going to reflect the people living in it?
If you were designing a house to sell, the questions would be very different. You would want the house to appeal to a larger market. You wouldn't want to make personal taste decisions that would turn a buyer off.
Staying neutral allows buyers to walk in and visualise their belongings in the space without, let's say a polka dot wallpapered wall behind the lounge.