Same here, my female had her front legs bitten twice by a mad shih-tzu, off-leashed... I gave shit to the owner but now, my dog remembers this and holds a grudge...
I don't thinik dogs hold a grudge... it's more something that will set his DA off. IMO mine got his nose bitten by one of the 3 french bulldogs and he wasn't to happy about it, let me tell you grabbed the lil shit and started shaking it around and I love the other owners comment after the whole incident "don't ever take your bad dog here anymore!" wtf? YOUR 3 dogs attacked mine while I warned you to keep them leashed but you didn't give a damn, but when something happens it's all about screaming at the responsible owner ? I know that Mace is forbidden in Canada... I'll check to get the pepper spray! lmao! both are forbidden where I live ^^ so that's unfortunately not an option...