For that, the Bears' coach is grateful.
There probably won't be much reminiscing when Chicago takes on New Orleans at Soldier Field this week, but Trestman did take some time to reflect on Thursday.
"No. 1, it was more about a friendship between Sean and myself," he said.
Trestman had just been fired after a two-year run as offensive coordinator at North Carolina State and was on a sort of sabbatical when he was hired as a consultant to Payton, the Saints' coach, for the 2007 season.
They weren't close friends at the time, but they knew each other from symposiums, back when Payton was an assistant in the league. They had attended symposiums and talked football over lunch a few times.
For Trestman, the consulting job was "an opportunity to have some dignity in my career."
Five years as the head coach of the Montreal Alouettes and two CFL championships later, Trestman is leading an NFL team for the first time. And he's off to a good start with the Bears at 3-1.
Chicago is trying to pick itself up after losing to Detroit and knock the Saints (4-0) from the ranks of the unbeaten.
The Bears are tied with the Lions for the NFC North lead. Their offense appears to be a better fit for the personnel, even if things have been a bit shaky at times, and it looks as if Trestman has connected with quarterback Jay Cutler.
That's something previous offensive coordinators Ron Turner, Mike Martz and Mike Tice could not do. And it's a big reason why he is getting this opportunity, even though he seemed to vanish from the NFL radar.
Trestman spent several decades coaching at the college and NFL levels under men such as Bud Grant, Howard Schnellenberger and Bill Walsh.
He developed a reputation as a quarterback guru for his work with Bernie Kosar, Rich Gannon and Steve Young, but by the time he took the job with New Orleans, he was in a sort of limbo.
"I had just been let go at N.C. State, I wasn't doing anything, I was sitting the year out, I had two years left on a contract," Trestman said.
"He invited me down and really showed professional respect. ... It was a great learning time for me and it was also a good time to watch Sean be a head coach and see how he worked on a daily basis and see how he handled the success and the adversity."
Payton called Trestman "a proven winner." But he was also a big question mark.
There was a knock that Trestman didn't relate well, didn't get along with other assistants, and that explains why he's a first-time head coach in the NFL at age 57. He seems to be relating just fine now.
Defensive coordinator Mel Tucker was quickly sold. The two had never worked together. But when he interviewed with Trestman in January, Tucker realized how alike they were.
"We have very similar trains of thought about the game, how to treat people, what coaching is all about, how to develop football teams and players, what is coaching and things like that," Tucker said.
A law school graduate with dark-rimmed glasses, Trestman looks and sounds more like an attorney or corporate CEO than most guys carrying a whistle and a clipboard.
His answers are thoughtful and detailed. And there's a quirkiness to him. Trestman probably was the first coach to address the physics subject of "string theory and different dimensions" with Cutler.
"I'm kind of reading a book right now," the quarterback said. "I don't even know what half the words are in the book, though. We just kind of kick it around."
Cutler wasn't sure of the book's title. And he couldn't really explain the theory, which has to do with the idea that extra dimensions exist.
It's just one example of Trestman connecting with a player, one of his most important players.
Backup quarterback Josh McCown mentions the lunch room. There's Trestman pushing in his chair and cleaning up his area and encouraging the players to do the same.
He just wants players to be aware.
"He just makes a point to say that's a way that you can serve the people around you," McCown said. "It's just a good example of the little things that you can do that maybe helps out somebody that's working back there in the kitchen, that doesn't have time to wipe up after you. The cool thing is there's never anything that's mandated. It's 'hey guys, think about doing it this way; think about doing it that way.'"