Let me start by giving you an example. Take a cup full with tea in it. Now if you pour some more freshly prepared tea into this cup, the tea will over flow as it does not have any space in it. But if we empty this cup and then fill it with the freshly prepared tea, you will enjoy the tea even more.
Like the cup already full of tea, we too are always full of opinions and assumptions for every aspect in life. Unless we completely empty our cups of the presumptions and opinions that we already hold, we will not be able to truly appreciate the new and fresh ideas that life throws at us all the time. That way we will be prepared to take all opportunities of life with the right spirit.