There's a hidden lesson inside the Last Crusade - choosing the Holy Grail scene, which I touched on in an earlier tweet, but I'll elaborate in full.
In 2013, I was utterly exhausted from pursuing the path laid down before me as a "IT Computer Specialist" and chose to abandon post-secondary for a life of leisure and exploration. Deep down, I wanted to make something of myself, and later on that year, I discovered the illustrator Yana Moskaluk, who was very beautiful and whose art was more beautiful still.
However, over a year later, she abandoned me at my worst as I poured out my heart to her and received nothing but her fearful silence, days after the release of Nolan's Interstellar.
When you reach a certain point in your life (and thereby your spiritual development), soon you'll begin to realise that those high-accomplishing people who happened to be blessed with a special interest in what they love, along with the circumstances to actualize themselves in this world - ought to be judged not by their accomplishments or potential to be (more) impressive, but by their fundamental character, and this is where wisdom ultimately wins over all profane characteristics.
The irony is that Yana and Katya would both fall heads over heels for an Edward Scissorhands, from the Tim Burton fable, but when finally getting to know a real person like him (me), they ultimately shirk away with an instinctual revulsion - proving themselves no better than the townsfolk who will call for his head when his deformed hands are used against him in a witchhunt.
As N. N. Taleb notes: "You shall be envied for your success, your wealth, for your intelligence, for your looks, for your status - but rarely for your wisdom (the true currency of Christ)."
What I really longed for from them was the ability to make myself and others around me happy and joyful, which was an illusion, no better than what David had sought for from the statue of the Blue Fairy in A. I. Artificial Intelligence (2001), which he had prayed to as a false idol in the hopes of getting Monica to love him back as a real boy, only for him to finally touch the statue two millennia later, and realise that it was just a statue - made frail from all the years of being encased in frost.
No better than the billions of people who turn to "Jesus Christ" or "Muhammed/Allah" for spiritual salvation, let alone guidance in their lives.
What true salvation in life really means is that it is essentially nothing (as in 'No Thing'). You cannot find it anywhere in this known plane of existence, apart from the realisation that you carry essential divinity within your own flawed mortal body - your consciousness and awareness itself which imbues life and meaning upon everything you experience and do as Eckhart Tolle would point out in plain words.
So, what happens with Donovan is essentially what has already happened with me pursuing someone like Yana in search of fulfillment, while the realization that the "Holy Grail" would not be made of gold is essentially you finding your real home again - in embracing who you've always been, even before you were born.