Always find people who are still stuck in the rat race have a very difficult time imagining a life without paid work. I also found it to be a transition to adapt to retirement but not a painful one. 
It is true that there are stages in life. There is a time to work and I worked as hard as most and maybe harder than many when I felt I had no choice. There is also a time for play before and after those work stages. One gets used to having time controlled by influences beyond one's control and leaving work behind opens up so much freedom. It took time to have it all sink in and to begin to create a new way of living.... routines and automatic behaviors gradually alter and the mind may even begin to entertain new ideas and beliefs, might discover a new time to get up and a different time to go to bed, diets and even meal times may stay the same or change to reflect more current conditions, clothing needs may evolve from work to casual. The list goes on...... so many doors open worthy of exploration.
That's what I love about my life and what I do all day. Primarily I just BE. I imagine. I think. I meditate. I walk. I read. I research. I love. I connect. I still cook a bit. I play with plants. I play with painting. I reflect a lot on life. I practice gratitude daily. I explore possibilities. How grand is that!
You can too. Ask me how. It all starts with the desire.