Headscratchers / Wallace & Gromit

• I know it's probably because of his lack of mouth, but Gromit never seems to look happy. They couldn't at least have his tail wagging?
  • It can be assumed that Gromit is happy whenever Wallace isn't in deep trouble. Thus eliminating 99.999% of their onscreen time.
    • And a fair chunk of their offscreen time as well.
    • One example in Curse of the Were-Rabbit is the expression on Gromit's face right after high-fiving Were-Rabbit Wallace before he turns back and discovers he let go of his safety line.
  • In The Wrong Trousers, he wags his tail as the newspaper arrives through the door.