That is a very good point; I agree they can understand abstractions to a point. I don’t believe trainers/breeders understand what intelligence means when they discuss “intelligent breeds” (they see it as ability to train, not capacity for abstract thought), but I have always thought the breeds closest to wolves have the greatest capacity for abstract thought. My smartest, a Chow Chow, could understand words contextually to a point. I once came home from a business trip, and she angrily grabbed my socks and started shaking them. I sarcastically said, “After being gone so long you are just going to get pissed and shake my socks? The least you could do is make yourself useful and fetch my slippers”. She had never been trained to fetch, and would never do what she was told at any rate, and had never been explicitly told what slippers were, but with a gleam in her eye, she dropped the socks and ran off and got a slipper from under the bed and dropped it at my feet, as I stood utterly amazed and dumbfounded. I’d swear she was smirking as she did it.
LOL! One might begin to think dogs are holding back and "playing dumb". They're thinking, "If I show off too much, next thing you know, they'll want me to run the vacuum cleaner".