I have always enjoyed going to see musical artists interpret their own songs as performers. I think of Bob Dylan's version of "Blowing in the Wind" from the "Love and Theft" tour. I saw him several times on that tour but only saw him perform that song once. The take was acoustic, but it was almost a country gospel version, and it remains one of the most powerful musical moments in my mind. Dylan's delivery seems to always be varied, as if he's continually digging through the characters in his songs, breathing life into them from the air in the concert hall. I also think of Bjork who performed songs from her entire catalog arranged for an all female brass band. There are plenty of examples, hopefully you've also had the opportunity to see an artist take on their own material with a fresh arrangement, like Steely Dan--while Walter Becker was still alive--reuniting after all of those years and taking on "Reeling in the Years" with a band more like the one that played on "Aja."
I get enjoyment from taking my own songs and putting them into a new context as a performer. Sometimes that takes the form of applying an entirely different musical style like making a ballad a reggae song or taking a punk tune and turning it into a bluegrass song or the reverse. In other cases it's the reality of instrumentation. I have a whole canon of work written for a seven-piece chamber rock group, and taking those songs and turning them into something that works for a three piece is more complicated than playing the cello and violin parts on my guitar and calling it a day. It sometimes requires a great deal of rearranging to arrive at a restatement of the work that feels fresh and true. These are drastic measures though; interpretation as a performer can be as simple as changing the vocal delivery of a line or the phrasing of a solo.
This is where the performing artist performs their magic. To take a work and to perform it in front of others is to interpret it for the moment, for that audience, for that space. Interpretation is a great power of the performer. It is an act of creativity that is unique and temporal, it dies immediately and lives on only in the minds of those who witnessed it and those who performed it. The performance - a dance recital, a play or musical, a concert, a reading - can renew our love for a work, open new doors on pieces we know in and out, or re-affirm ourselves and our beliefs.
Painters must leave their paint to dry. To come back to the canvas with new pigment is to forever alter the original statement. Writers must publish: the words of an edition are set. If they are later edited, the story and the impressions it leaves change. The parallel for song writers is the recording; the notes played, the microphones and preamplifiers used, the arrangement selected forever burned onto tape or bits.
There is an illusion in all of the above that these are works for the ages. That they are completed. However, I would argue that only the intent is complete. As soon as the last stroke is painted, the last punctuation written, the final note decayed, time begins to pass, and time will have its way with the idea of permanence. There are the physical effects, present in all analog creations, the decaying of the pigments, the yellowing of the pages, the loss of magnetism on the reels of tape. Additionally, all works are subject to the shifts of perception, understanding, and culture which happen over time that forever alter the lens by which a work is seen. The dialog from the work is one that involves the work in time and the viewer.
The performing arts allow another player to enter into the mix, the work - the composition, manuscript, play, poem or other is the creator's intent. It still exists in time, it is subject to the same patina of perception that time bestows on all art, but it's more like a recipe than a finished work. We have the viewer, or the audience, and the lens they bring to the work. The new player in this equation is the performer, the producer. This is where the magic occurs, where the moment of delivery can change our understanding of the work entirely. A musical phrase played just a hair slower or with more legato or staccato, a phrase read under the breath, a broad gesture of the arm instead of a small one, a dialog between characters where they face away from each other instead of towards. It's why we go back to see "Hamlet" or "Hamilton" over and over again, because each performer, each performance can bring us something new. That's the power of interpretation. That's performing the moment.