It is not a good idea to generalise about the temperament of breeds. Just as all staffs are not killers, all labs are not soft and gentle cuddlies. I am involved with a lab rescue and labs often come in with temperament problems, mostly due to the treatment they have had, but sometimes because that's just the way they are. Some even have to wear muzzles for a while before they can be trusted with other dogs.
We tend to put our lab and lab cross on a lead if others do first, always assuming they are doing it for a reason, and also, with the pup especially (she tends to run if a dog is too pushy, then gets chased) if we come accross a dog we know is out of control. I honestly don't find it a problem to put a lead on the dogs, they come when called (usually!) and the last thing I want is them to upset anyone.
On the other hand, yesterday we were in the park and came accross a woman with a young staff and a dalmation, no collars, and the staff charged up to me and leaped up and landed on my chest. She was very wriggly and friendly, but I walk with a stick and fall easily, the only reason I didn't this time was because I braced myself with my stick. There was no concern from the owner, just an assurance that she was playful, not nasty! I detest dogs running up to me and I'm sure others do too.
And that includes labs!
