The Wyvern is a wonderful creature. While I won't admit this to the dragon kind even if pressed, a wyvern is most comparable to a dog. They like people and are very attentive and protective. DJ Conway discusses guardian dragons in her book and her descriptions fit wyverns much better than other dragons from my perspective.
Wyverns are the watch dogs of the dragon world.
It's their job to see what is coming toward them and protect their chosen people from harm.