Normally, when we are free from any physical suffering and encounter no difficulty in our daily life, we think the world is so good that we do not feel necessary to be mentally or physically prepared for impermanence. Just relax and idle the time away. Should some misfortune befall us, we would likely be caught off guard and much distracted as to what to do. By then it may be too late to even turn to the Buddha as a last resort.
[Excerpt from Luminous Wisdom Book Series 1: The Right View ~ The Three Supreme Methods]