Protective Dogs: Endearing Or Problematic?

I adopted my dog Jayda about six weeks ago after I began working for a pet insurance company. We bonded quickly and within days, people were already commenting on how much she seemed to love me.
Almost overnight, our bond got a little too serious. At the Pets Best Insurance office, shed growl and bark at anyone who came near me. At home, shed snarl anytime someone came to visit. At the dog park, shed snap at other dogs if they came too close to me. And anytime I drove through Starbucks, shed bark and lunge at the window when the barista reached toward my car.
A quick Google search on dog health care turned up what Id feared: Jayda was showing territorial aggression. People would say, Oh cute! Shes protecting her owner! But of course, Jayda wasnt just protecting meshe was being obnoxious and scaring people.
I read that the best way to deal with territorial aggression is to teach the offending dog that its human is the pack leader. Pack leaders dont need protection and dogs instinctively know it, so they dont need to scare anyone away. The second aspect is instilling confidence in the dog so she starts assuming the best of strangers instead of the worst.
In addition to obedience classes, I started making small changes at home. For example, I stopped letting her jump up on the couch whenever she felt like it. Instead, she had to be invited. After a few days she began to understand that I was the pack leader.
I also made her sit before she received anything from me, including her meals. When she became defensive outside the home, I removed her from the situation and made her sit quietly to show her that I was in charge. At drive-thru windows, Id praise her being quiet before we approached the barista and throughout the transaction as long as she was quiet. Over a few visits, her barking and lunging tapered off into just one bark, then one muffled woof, and now nothing.
Lately people have been telling me Shes like a different dog! Jayda hardly flinches when people come in and out of the pet care insurance office, and a tiny squirt from a water bottle calms her down when she slips-up. Shes quiet at home and friendly at the dog park. We took our first camping trip last weekend and she was extremely well-behaved, even staying quiet most of the time when the other dogs barked.
If something is odd about a situation or she hears a noise at night, Jayda still gives a low warning woof. I think this is the perfect balance a friendly, sociable dog wholl only alert me when she thinks its really important.
If Ive learned one thing from adopting Jayda, its that dog health care is multifaceted. Theres much more to owning a dog than feeding and walking itits also part psychology.