One of mine is quite the enforcer and loathes rude young male labs and golden retrievers. She goes about her business in a watchful and slightly menacing way until they come into range, then just stands and waits as they barrel up going, 'Hello! It's me, I'm absolutely great, my name is-' Then, as their face goes into hers, she tells them loudly TFOTTFSOFATFOSM, and chases them a few paces.
I've never known one not immediately back up, submit to her evident superiority and come grovelling back in going, 'Terribly sorry, I didn't know you were so tremendously important, I won't do it again!' Her reaction is very much, 'Cool, all good, off you trot now.'
Most owners are well aware that their full of himself young dog had it coming. The odd one has an attack of the vapours. 'Ooh, she's quite aggressive!'
She's not at all. She's probably just saved your dog from having his head kicked in by another, less tolerant, dog in the future.