I never had a problem with previous dogs...but I'm probably just remembering adult days.
What I have now will be of no worth to you but I'm gonna share anyhow because you made me think of it and chuckle.
Danny is trained. He was so easy, so willing, really the smartest dog I've ever had (with apologies to my female Akita whom I always thought of as brilliant)...just a real joy.
He didn't get his smarts from Sunnie. She is a Duh O G. Sorry Sunnie. I'll cut her some slack....she's neurotic and anxious.
Anyway, if I give Sunnie a command, "Sunnie, whatever"....she will cower and look guilty. It's as if she thinks she's doing something wrong if I had to tell her to do something different. I don't yell at the dogs but even if I'm using a "less than normal assertive" voice, or a whisper, she will cower. And don't even ask me how she reacted to the word "heel" (I use the word "close" because of her reaction...somebody was heavy handed with that.) [the shelter had actually told me "a harsh voice will devastate her"...wasn't going to be a problem in this house]
So if I want Sunnie to do something, I usually say, "Puppies, whatever". She then knows that both she and Dan are expected to do the whatever. She usually does, but not always.
Every now and then I'll try just saying "Sunnie, whatever" and Dan is the only one to do the whatever (unless they're not standing together and he sees me looking at her). He just wants to please.
Basically the only training I've been able to give Sunnie is what she's seen Dan do. She just doesn't get it. I blame the anxiety...which we have only a tiny bit of a handle on (courtesy of Chinese teapills).