The fromer military officers I know that crossed paths with Mattis say - Mattis is all about Mattis. His brand is all he cares about.
“Mattis is all about Mattis.”
During Desert Storm I was a Red Cross Volunteer at Walter Reed on the amputation ward.
Got to see a lot of generals. Most were the “Look at me! Look at me!” type.
A few were “How are my men” type. Petraeus was like that. We (volunteers and enlisted) didn’t know who he was until he was leaving the floor!
He would come by occasionally. Just sorta quietly wander in. So different from the clowns that would stride in with their entourage.