You say you have been bitten. That bespeaks of a misread of a dog's attitude or motivation. To that dog for reasons known only to it, you presented a threat, and it protected itself and/or its owner. By stopping and slowly backing away without looking the dog in the eye you would most likely have defused the situation. Unless it's in full-on attack mode (which I've never seen), a border collie can and may nip and lightly worry at an intruder. That's how they move whatever they're herding.
I'll let Salamander tell you what a Dobie can do.
Here we go again. I must announce to you that your statement is without your presence when that incident took place, and it is presumptuous. Your assumptions are wrong, as are your conclusions. Don't dabble in giving your opinion based only on your preconceptions. But I will tell you that I will not surrender my right to come and go as I please, to a state of being required to psychoanalyze every dog I come across.
In other matters, respectfully --