Have you ever noticed that there are 3 phases of playing a song on piano?
1. New and fresh
When we first learn to play a song on piano, it's a process of discovery. "Oh, the C chord leads to Em." "Hmmm... what voicing should I use on this F#7(b5) chord since there's an E in the melody?" "The bridge is 10 measures long."
2. Having fun with it
Once we get over the initial learning curve, we find that we can play the song and we begin to express ourselves through it, improvising various rhythms and perhaps finding new ways of phrasing the melody and improvising over the chord progression. This phase can last for a long time.
3. Deepening over time
If we revisit the same songs year after year, we find that these pieces grow with us, because our relationship to the pieces grows and deepens over time. (Same with classical music like Bach's Preludes and Fugues.) They become like old and dear friends.? The chord progression that once seemed strange and new now feels completely natural and we can improvise melodies that wouldn't have occurred to us in the earlier days. The melody taps into feelings that we had forgotten we ever had, and evokes memories of a previous time in our lives.
Once we understand this process, we can embrace it and live our musical lives more fully.