In my opinion - Dogs on leads.

[Stu]

Oh that's a good point Loiner.
My dog is absolutely horrid to other dogs when on the lead. She lunges and barks (but doesn't bite - she's a Sprocker and it's not really in their vocabulary). But it's a reaction thing.

Off the lead she neither barks nor shows any aggression and runs away squealing if anything lunges at her.

 

[Clint]

It's because you're probably tensing the lead sending signals to the dog. Try a floppy lead..