In what ways did your dog “mellow out” or “clam down” after adolescence?

I’m dealing with a slightly crazy 7-month adolescent cattle dog rott mix. I keep reading that around 18 months to 2 years, dogs start to mellow out or calm down. But what does that really mean? How did your dog’s behaviors change after adolescence? What are some examples of them “mellowing out”?

Do they start ignoring other dogs on walks better? Do they start ignoring other people? Are they less aroused by the environment?