Looking at your past selves lets you see the tiny seeds of thought that grew into prevailing patterns and frames that you take for granted now. And you learn what worked and what didn't, what was important and what wasn't. This is wisdom.
You are a four-dimensional being. You have definite bounds in length, width, height, and time. And you can cast your consciousness through time: into the past through memory, and into the future through prediction and planning. Are you acquainted with your one-year-ago self? With your future self?
Thiel’s diagnosis of "indefinite optimism" in startups also applies at the personal, life-planning level, and I’ve found it to be a really useful, if scary, tool for that. What are the pleasant future daydreams that you passively hope for?