Many of us have cycling goals and some for different reasons. Some like the thrill of saying I did this many miles in that amount of time just for the sake of the bragging rights. Some like to continually up the goals seeking a higher faster speeds and more miles. These are unsustainable goals at our age (or any age for that matter), IMHO they will turn cycling into a job, or worse - a prison. The trick is sustainable motivation. If I was purely motivate buy the "fun" of cycling, I would ride only on a limited number of days when it's not to hot, not to cold and not too many hills. I ride a lot because it is fun, but I also force myself out on long hard training rides because I know that in the long run it will make everything else I enjoy doing that much more enjoyable. The harder I push myself at riding for exercise the more enjoyable riding for pleasure becomes (about 1/3 of my rides are for the shear fun of it), the better I can ski, hiking is easier and working around the house is easier. When I am fit and strong from riding, I am able to enjoy a life full of a lot of other things more.
Denver did not understand why some of us talk about farther-faster goals, when I talk about such things this is why. There is a little ego in there, but that only gets me so far. The real driver is being fit for the rest of my life's activities.