@Boomclaps Agreed - it wasn't a 'dig' but more an effort to illustrate to the OP that there is training and there is training.
By six months old a puppy is likely to be toilet trained (mostly), know how to sit and come when called and probably quite a few tricks too. But they won't yet know how to behave like a calm, adult dog in all scenarios. They are likely to get over excited, over stressed and boisterous. Perhaps even scared still as a fear phase kicks in. They may appear forgetful, stubborn, wayward, rebellious, aggressive, reactive and more - (many of those words don't strictly apply to dogs but form a nice way to describe the behaviour so that people understand what I mean).
At that age, they need time and patience and all the support you can give them to come through it to the other side. Some dogs do indeed, sail through their teenage months like nothing is happening. For some it lasts a few weeks and is over. For other a year or more of really poor behaviour ensues. For some dogs all that lovely acitivity and training you do with yours keep them well entertained, well behaved and well happy. For others it might be too much and they would need it to be dialled right back. The thing is, when you have a baby that needs to go to baby group and you need to take the dog because it's young and struggling to be left, you may not have the option to dial it back a bit - just one example.
When the dog goes through a fear phase and starts barking and lunging at other dogs in the street, this is much, much easier to handle if it's just you and the dog vs you, the dog and a pram with a baby.
When the dog gets over excited and jumps up and knocks over an ornament, that is easier to remain calm than when he jumps up and accidentally scratches your baby.
When the dog has had perfect recall for six months and then buggers off after a hare three fields over (or a cat three streets over) it is awful and stressful. But it is easier to run after the little bugger if there's just you, vs you and a baby.
Conversely, walking a dog twice a day, day-in, day-out in the rain and sun and hail and snow can be drag when you've had a full night sleep - especially for working breeds that tend to benefit from "proper" dog walks over field and forest etc. It's enough to break you when you're on your 100th night of little sleep, the washing is piling up, the house is a mess and all you really want is a hot bath and to go back to bed.
Of course, not all these things happen to everyone but they are all normal puppy/teenage occurances and so any/all could happen.
You'll know all this, so I am merely elaborating for the OP's benefit 