They are hard dogs. They really don't care to interact with many people other than those familiar to them. Just based on their job, they shouldn't, they should be all business, focused on the task and what needs to be done. Mine are silly with me and with each other. We play and tug and rough-house, but business is business.
My dogs cannot be handed off to other people for training or performance. Some people think thats a bad quality, but I'm indifferent. They obey others depending on what it is, but my herding trainer wanted to take Zen and show me what she was taking about once. He would not perform for her. He had zero interest in working for anyone but me. Makes it hard at times, because of situations like that. Or if I was at an agility trial and hurt my foot or something, I'd just have to pull for the rest of the weekend. They will do it without me, to a degree, but really see no point in working for anyone else. I can leave them at a boarding kennel and they will kennel-up for whoever and come in or go out when asked, they aren't difficult, but that person probably wouldn't be able to get them to go through 100 commands without a sideways glance and a "whats in it for me" attitude.
I have always been told (by non-acd people) that my dogs were the softest ACD's they had ever met. I can't tell you the trick to that because I didn't train them any different than I would a golden or bc. My dogs work for me. They enjoy their work. Just because this is a hard breed I don't believe that neccessitates punishment based training. Not saying I haven't hauled off and whacked a dog well deserving of it, but thats not how I train behaviors. I think this breed too often gets into the wrong hands and gives people the wrong impression. Just like pits. Yeah, its an ACD, but yes he/she can behave normally because I won't accept anything else.
But yeah, mine get the butt wiggle, and the zoomies, and my male is about the goofiest, doofy ACD I've ever been around. Most males are more goofy, but I expect him to mature and become more serious at about 4 yrs old. That's generally when I've noticed that they get their brain.