Yes, exactly - I don't want a dog with high suspicion because my dog is my day to day companion first and foremost, and that means I take him everywhere I can with me. Trent is very stable, breezes through large crowds when I take him to sidewalk sales, and while he doesn't look forward to meeting new people, he's been known to fall in love with strangers once or twice
He allows people to walk through our door if someone is there to greet them, and even then if guests walk in unannounced, he'll alert bark at most. A frightening display, but with no meaning behind the action. He hardly bats an eye at people walking past our house or our car, if we're in a parking lot.
But, if he senses any genuine nervousness or fear from me, he jumps into action (and I admit to scaring easily). And not as a human or fear reactive dog would. Luckily, it's always been false alarms and a pat on the side or a "it's okay, Trent" calms him down almost immediately. He's very conscious of me even when he is acting on a perceived threat, and has displayed excellent discernment in the past.
It helps that he is 3 1/2 now and finally growing that brain of his
In dog less self aware or mentally balanced (whether due to age or maturity), or in a dog with lower thresholds and stronger suspicion or a sharper temperament, this can become something that is difficult to manage... especially if handled by the wrong person. Some traits inherent to the breed can be misinterpreted and then mishandled, or simply not recognized or dealt with at all.
Even in a lower drive, higher threshold, "pet quality" dog like Trent, it took a while for me to really know my dog and what I had (and by that, I mean a great dog and a poor personal understanding of the type I owned
). As a first time dog owner, I managed well, in my opinion, and without much effort to be honest. Just a basic understanding and the realization that my expectations weren't very informed. So if someone wanted a dog that would not display aggression, then I'd definitely recommend against German Shepherds, among many other breeds.