Although I know the question I posed is impossible to answer in a single word or sentence, since it would take a full-length book to address some of its implications--and even that would likely end up being largely subjective--I am, having just read the latest novel by Julian Barnes, tempted to respond with one word: intelligent.
The Sense of an Ending, which at 163 pages can be completed in one sitting, is an amazing achievement. The few main characters come alive with sprightly dialogue, an equally lively narrator-protagonist, and deft description. For example, Barnes describes the first sight of the "Fruitcake" who haunts his protagonist's life as follows: "About five foot two with rounded, muscular calves, mid-brown hair to her shoulders, blue-grey eyes behind blue-framed spectacles, and a quick yet withholding smile." That tells us a lot in one sentence.
The narrative, which is filled with reflections of regret, nostalgia, and desire, moves along quickly, with a surprise at the end, and manages to deal with some important ideas, chiefly time and memory but also love, death, suicide, sex, jealousy, and aging, among others. It is a clever book, as the Brits would say, and it is very English in many ways.
When I pick up such a novel, I look, of course, at the opening to see if it is original or engaging enough to interest me. I look at the style, and here I find sentences that unfold with effortless ease, conveying an intelligent male narrator who makes every word, every sentence count. It is all done with what the Italians call "sprezzatura."
The tone with its questions is elegiac, reflecting on the vagaries of memory. On the first page: "What you end up remembering isn't always the same as what you have witnessed." This becomes a running theme, elegantly stated yet conversational, as if we are overhearing a man look back forty years to the friends of his youth and wonder if he ever knew them; and we the readers are flattered to be included in his ruminations, which are by turns witty, bawdy, colorful, and always analytical as we think, too, about the slippery nature of time.
Tony, the novel's narrator, asks, "If we can't understand time, can't grasp its mysteries and pace and progress, what chance do we have with history--even our own small, personal, largely undocumented piece of it?"
It is rare to find a novel of ideas that has real feeling conveyed so concisely, but then this is Barnes' 14th novel and 17th book: he knows what he is doing. His style is enjoyable, varied, a model for writers, yet we hardly notice it as we move swiftly to the conclusion of the book, where we find no easy answers to the many questions the narrator has raised. "Time grounds us, then confounds us," we are told.
I can easily imagine a film (for viewers of a certain age) based on this novel starring Bill Nighy, with his clipped, detached, bemused manner, and directed by Steven Poliakoff, who has done a lot of films involving time and memory. He would enjoy the question posed so well here: How far can we go re-imagining our younger selves?