Here I've tried to find examples of the cantankerous for further research and reference.
Hugh Laurie's character, House, is a prime example of a cantankerous man. He saves lives - but most genuinely find him particularly difficult to work with.
Here's a clip of a typical dialogue exchange with his character, in the form of his auditioning.
Carl Fredricksen from Pixar's Up also begins as a cantankerous character in the early stages of the film.
Carl's first encounter with Russell is also a prime example (youtube won't let me embed).
A random cantankerous puppet
Another cantankerous example, yet with some strong language so be warned!
A scene from Spongebob with a weird cantankerous character. Stop watching after 0:45 secs as it gets pretty random after that.