Pixel does have some barrier frustration when he's on lead and meets another dog. We're working on "pressure = yay!" Pixel, being a guard dog/alert dog breed, also takes a touch of time to warm up to strangers at the house.
I've had an electrician in my house for 4 hours. To make everyone's life easier, I've kept Pixel separated from him so he wouldn't have to re-establish himself as protector of the house every time the electrician walked by. (No aggression, just a lot of show until he realizes the person won't kill any of us.)
On a whim, I attached Pixel to my chair as I've worked on homework. And Pixel has not said a word to the electrician since. I don't know if it's because he's used to the person being in the house, or if it's some comfort of being tethered. Maybe because he realizes he doesn't have to protect the house if he's tethered. Whatever the reason, I'll be experimenting with this a lot more. I don't mind the initial alert, it's the 3 or 4 additional "You remember I'm watching you!" barks after the person has been here for a bit that bug me. Especially since within 2 or 3 minutes of the person no longer coming in and out the door, Pixel tries to get into the person's lap and follows the person like a Labrador after food.