Why ?

[TheEpsilon]

My 8 year old Labrador ( Bitch )is the softest dog you could meet . She loves to be stroked & petted by everyone .
But the bloke down the street walks past with his two Rottweilers , and my lab goes mental .
If she's in the front garden , she will physically try to get at the Rotty's .
All other dogs , she wants to play with .

[denisegordon]

I think dogs just get a look from other dogs, we know as humans that someone can just look scary without any justification. My dog hates some dogs so I just assume they are communicating in some way we don't understand. Try distracting her with play or food to take her mind off it and giving her a treat when she is calm.