A pure-bred Labrador Retriever bitch, this dog had far more personality and intelligence than I've ever encountered in any other member of the genus canis. I acquired her when she was approximately 2 years old, and despite not having a chance to work with her as a pup, she was the easiest of dogs to train. She was eager in all things, which I expect made the difference.
Her entire life was playing Frisbee, and she was very good at it. She would catch it on the fly maybe 80% of the time, and it was fascinating to watch her follow a long throw, outpacing it and getting into position with quick glances over her shoulder.
She was the very acme of persistence, and if she did lose sight of the object of her desire, in tall weeds or whatever, she would quarter and search the area systematically, for however long it took to find the Frisbee (or tennis ball, golf ball, stick, or whatever). Once I tossed her Frisbee into a pond, and it sank and was lost. She refused to give up, refused to exit the water, and after about 20 minutes I was concerned that she would stay in until she became exhausted, and perhaps drown. She completely ignored the sticks I tossed into the pond as a substitute. I finally had to hike a half mile back to the house, get another Frisbee, and return. Even then she gave me a look which said "Hey, I know this ain't the right Frisbee!", but at that point she'd been swimming a search pattern for nearly an hour non-stop, and her exhaustion was such that she deigned to fetch the second Frisbee to shore.
Perhaps her most amazing fetching trick, though, was to retrieve a golf ball hurled at point-blank range into a soft snow bank. She would dive headlong into the snow drift and completely dismantle it, until she found the golf ball!
I still miss her.