I didn't want a difficult dog. We'd already had a difficult dog — Riley, who died in November 2017 at the age of 16, and who lived a long, happy life but spent his first 10 years terrified of bicycles, small children, in-line roller skates, vacuum cleaners, loud trucks, other dogs, thunder and houseflies.

I loved Riley down to the ground. But I had to be cautious with him, all the time — avoiding busy areas on walks, keeping him kenneled when workers came over, watching when we approached a blind corner in case a small child or a bicyclist came dashing around the bend.

It was hard to walk freely with him, mindlessly, the way I love to walk, the way I walk with Rosie (our non-difficult dog). (Oh, Rosie is an easy, easy walker.)

When Riley died, I cried for days. And then we adopted Angus. A puppy! A new beginning!

And dagnabit, now we have another difficult dog.

At home, Angus is the sweetest, mellowest dog we have ever had. He smooches me awake each morning. He is cheerfully submissive to Rosie, even though he outweighs her by 10 pounds. When he's out in the yard, he races toward the house the minute I call his name. He's joyful and funny, a happy dog.

But out in the world, he is on high alert. I can't walk freely and mindlessly with him. He pulls on the leash, scanning the route ahead for rabbits and squirrels. When he sees people, he often barks (and he has an impressive bark).

To be fair: Angus is good about 90 percent of the time. But that last 10 percent keeps me on edge.

In February, we brought him in for his annual checkup. It had been a year since he'd seen the vet, and Angus didn't remember him. So when the doctor rolled his chair over to take a look, Angus — who had been cowering against my husband's shoulder — growled.

The doctor quickly rolled his chair back again.

He then suggested that he take Angus into the back room, away from us, to conduct the exam. He thought Angus would relax if we weren't there, but if he didn't, they'd put a muzzle on him.

As it turned out, no muzzle was needed. Angus turned sweet again in the back. The vet sat on the floor and Angus crawled into his lap, and the exam was conducted with lots of training treats and no trouble. (And a vet tech took a picture for us, as proof.) But when a second doctor happened by and stopped to admire Angus' funny ears — Angus growled at her.

He just doesn't like strangers. He doesn't like new situations. And it kills me that my beloved dog isn't fully comfortable in the wide world.

The vet assured us that Angus is not aggressive. "If he were aggressive, he'd be barking and lunging," he said. Instead, Angus growled to let him know that he was uneasy and that he wanted the vet to back off.

But still. I can't have a 58-pound dog that growls at people. I can't have a strong dog that pulls me down the street. And I don't want a dog that will force me to spend the next 16 years walking cautiously while peering around every corner.

I love this dog down to the ground. So what do we do?

There's really only one solution: more training, more training, more training.

I have made an appointment with a new trainer. Angus and I have some work to do. I'll let you know how it goes.

Laurie Hertzel is the senior editor for books at the Star Tribune. • 612-673-7302. @StribBooks

Follow Angus' adventures regularly on this page, and catch up on previous stories at startribune.com/puppy.