On Thursday, in the hands of Thomas — who made his conducting debut with the San Francisco Symphony 50 years ago, with Mahler’s Ninth — every few minutes yielded a new delight, from its alluring first measures to its thrilling ending.

Once or twice during the music, one noticed his health as he steadied himself by grasping his left hand on the podium. His conducting retained its rhythm, even if it lessened in dynamism; he rarely called for volume adjustments, or vigorously punctuated key moments. At one climactic downbeat in the first movement, the strings, brass and tympani all landed just a millisecond off from each other.

But this is Mahler. Every cell in Thomas’ body knows this music. The orchestra does, too, and rose to the occasion — especially in the beloved Adagietto, one of Mahler’s most heart-wrenching pieces of music. (Thomas’ mentor, Leonard Bernstein, so loved it that he was reportedly buried with the score.)

It was during the Adagietto that I couldn’t help but meditate on Thomas’ long history here. Personally, I thought back to first seeing him at Davies in 1995, conducting Stravinsky with violin prodigy Midori; again in 2001, valiantly conducting Mahler’s Symphony No. 6 one day after 9/11; and in 2015, premiering the groundbreaking SoundBox series. He’s inspired multiple generations in the Bay Area (the Mahler vinyl bins at Amoeba Music are, as of this writing, completely sold out), and is indelibly woven into the cultural fabric of San Francisco.

After the piece’s rousing finale — before the audience spilled out onto the newly christened “MTT Way” — Thomas stood for a seven-minute standing ovation. It would have gone on longer, too, were it not for him theatrically sighing and miming to the enthusiastic crowd that it was time to drink milk and go to bed, drawing laugher among the cheers.

As if to console anyone with tears in their eyes at this celebration of life and an incredible career, for a second, at least, the message was: don’t be sad.