Despite being nice and enthusiastic, my first three Newfies were a bit rubbish at retreiving (unless you are a drowning victim... or a boat!) they might bring back a stick once or twice if you are lucky - i think they can't see the point... and who can blame them! We throw a stick, they seemingly heroically rescue it using all their inbred instincts and then we chuck it back in to drown!
Martha though is a whole other kettle of fish... she'll happily chase in and out time after time after sticks, so for the first time i've been able to confidently fish out some of the floating toys i've accumulated over the years safe in the knowledge that she'll bring them all safely to shore when it's time to go home! I think she might be a retriever in disguise!