Music by John Williams brought me so much happiness that I had to go right back to the beginning and watch it again.
A film that reminded me why I got into this business in the first place, a film that will send you back to your DVD collection, your favourite streaming service or - if you're lucky - your local video store.
The new documentary Music by John Williams restores your faith in the power of cinema to transport you - to make your day better, your life better, the world around you look and feel better.
John Williams is 92 years old and still working. His most recent score was for Indiana Jones and the Dial of Destiny last year.
I thought I knew a thing or two about the great man - after all I know so many of his iconic themes - but this film told me so much more. He was already 40-years-old, and had been working in Hollywood as a musician, arranger and composer for 16 years, when fresh-faced Steven Spielberg knocked on his door to ask about The Sugarland Express in 1974.
Williams' father was a professional drummer, at first on radio in New York backing artists like Benny Goodman and Tommy Dorsey.
Then, when Williams-the-younger was still in high school, the family moved to Los Angeles and he played in orchestras for all the studios, exposing his son to the grind of motion picture music scoring.
The young Johnny Williams was in love with jazz and wanted nothing more than to play piano professionally but the need to make a living and feed a family - and his reputation for working fast - meant he was soon in demand as a session musician.
That's him playing piano on the soundtrack of To Kill a Mockingbird in 1962.
Television scores and then feature films found him. His first Oscar was for arranging Fiddler on the Roof, but he was also getting a reputation for disaster movies - not bad films, films about disasters - The Poseidon Adventure, Earthquake and The Towering Inferno.
When Williams and Spielberg found each other, one of the great partnerships in the history of cinema was born.
During that 50-year relationship, Williams has only missed five of Spielberg's films and in the documentary Spielberg talks about how - on every shoot - whenever it gets tough he dreams of spending a week in the scoring studio, watching and listening to the maestro at work.
His famous opening bars from Jaws , "His musical shark worked," Spielberg says. "My mechanical shark didn't," are rightly famous.
But one of his most extraordinary achievements came next with Close Encounters of the Third Kind.
Williams was challenged to come up with the crucial five note motif that haunts the film, and then the phenomenal musical arrival of the aliens at the climax. He was, to all intents and purposes, writing their dialogue and he should have been given a screenwriting as well as a composition credit.
The documentary is produced by Ron Howard's company, Spielberg's Amblin and Lucasfilm, so it's obviously going to be a celebration of their joint achievements, but that clip gives you an idea that there are some fascinating musical details that a genius like Williams is able to share.
Questions about the future of motion picture scoring, and the fact that Williams' love for the symphony-sized orchestra was already a bit of an anachronism back in 1974, come up.
The clash of cultures as classical musicians at the Boston Symphony are forced to play "trashy" film music at Williams' Pops concerts in the 80s - they hissed at him in rehearsals - has eventually been overcome by the fact many of the current generation of classical musicians fell in love with orchestral music thanks to hearing Williams' music for Jurassic Park at their local movie theatre.