The fast, the furious, the calm and the serene - dog walks for all.

Its true that not all dogs are up for that. Some dogs are naturally timid, some dogs too young, some too old. Dogs have the same wide spectrum of 'personalities' that their human owners have.
Then I got that many walkers are females who can be intimidated or downright scared of high speed fast moving dogs either harming themselves or the humans around them. If you have ever suffered a high speed dog running into you it can be more traumatic than the worst sporting injury that you have ever had.
If you expect that to happen, have had it happen, or generally don't get the whole mad dog play, then yes full on play can seem quite scary to quite a few people. That includes men, women and children alike.
And if you don't know where to stand, how to give the dogs a safe space or move them on far enough away from you, you can risk damage. But perhaps that is the whole point of why many people hire dog walkers. We don't get paid danger money, but perhaps we should.
Its true that not every walk has a frantic play, but you can't always predict what dogs you are going to meet and how dogs in your pack are going to react or play with new dogs. some dogs just click and give each other permission to go berserk, in a good way.
At the moment I have a couple of dogs in my pack that particularly love playing with a big friendly bull arab in the park. And this is one of the most social big dogs there is, but it is young and just wants to run and play and puppy wrestle. So it looks for dogs to do that with, and typically picks wisely with dogs that want the same. Often they are members of my own dog walking pack, while the other members of my pack just choose not to participate. Whether its a size thing an age thing or other, its all choice and they all get what they need and want.
The thing is that just as many if not more dogs don't participate in continual full play. For instance my dog is nine and he will get involved when the energy of the play gets near enough and frantic enough for him to be motivated into action. I walk other dogs that keep their distance from such play and prefer acting as look out for the pack and themselves.
This post is just a salute to those dogs who can play hard and want to play hard, socially. They make the walks exciting and they get what they need, in a safe dog park space. Thank you for making my days !