All of us suffer from a phenomenon known as the "end of history illusion". Essentially, we tend to underestimate how much we will change in the future. For example, everyone looks back and thinks, "I can't believe I did those stupid things"; "I can't believe I was so wrong/silly/impulsive"; "I can't believe I really liked that food/hobby/band"; "If I only knew then what I know now..."
Although most people acknowledge that their lives have changed even in the past decade, they generally underestimate the extent to which their personalities and tastes will shift in the future. We like to concentrate on our present wonderfulness and think that the person we are at the moment is who we'll be forever. Yet, change is inevitable and change is constant. You're never going to be the person you expect to become for the rest of your life (unless it's one second before your death).
However, I think there is an even more important reason why people don't accept how different they'll be in the future: "If I am going to change, it implies I'm not so terrific now."
I choose not to look at it that way. Instead of seeing yourself as someone with a bunch of flaws to correct, I think it's a better attitude to consider the changes as opportunities for growth. You're expanding your horizons and having new adventures. As I mentioned on-air, I was a little unhappy about turning 66. It just seemed old to me. However, I decided that instead of this being my slide down, it was going to be my slide up. Recently, I've been doing a lot of work with metal and jewelry for my Dr. Laura Designs store. My motivation is to keep learning how to use new tools and master different techniques (sometimes I drive myself so crazy that I have to close the door of my craft room and watch a movie to get my brain to leave me alone for a minute). I keep myself in a constant state of learning with my crafts, program, and life in general.
It's also important to accept that you're never going to be perfect. When I'm filing a piece of metal, it seems like a never-ending process. I do my best to file away all the tiny imperfections, but no matter how much I file, it's never going to be perfect on a molecular level. However, I don't stop trying - I just accept that it won't be perfect. Striving for perfection without accepting that there isn't any is neurotic.
I think that's the best mentality to have in life: accept that you'll never be perfect, but keep putting your best effort forward. We will all die one day and we still won't be perfect. However, instead of sliding down the ladder because we feel like it's no use, we need to keep going up. As long as there are still steps on that ladder, we need to climb them.