Boone is the same way. He doesn't like Boxers, he had a bad run in with one when he was 5 months old, there was a huge (100lb+) Boxer with no manners what so ever, not aggressive but very hyper, playful and rough. The owner just let him do whatever at the park stood far back and watched. Poo,r then 25lb Boone, didn't stand a chance when the Boxer turned to him. I attempted to get Boone out of there and the Boxer ended up knocking me over, Boone took off but I couldn't get up, the Boxer just kept pouncing on me. Other owners came over and one guy actually grabbed the dog and literally threw him off me then ripped the owner a new one. Friend has a very submissive Beagle/Lab mix, but she's only submissive to Boone and constantly goes over to him, licking his muzzle, rolling over, peeing etc. Boone harrasses her to no end.
After Drifter passed anytime Boone saw any black, Lab like dog he'd get so excited. I guess he thought it was Drifter. He would be so dissappointed when it turned out to not be Drift. He's not so bad now but still gets a little excited at times.