Pets are very sensitive to their owners moods, often mimicking them by becoming happy, excited, or melancholy along with their owner. In TV Land though, some pets seem almost to be living emoticons for their owners' current state of mind. For example, the Right-Hand Cat
of a Diabolical Mastermind
will hiss along
with their Evil Laugh
. Another character's Head Pet
will (perhaps because of the proximity to the brain) even gesticulate along with their owner.
One interesting duality is if the owner is very elegant and refined while the pet is crass. An owner being snide to someone may be echoed with the pet jeering. An owner menacing someone could be mimicked with the pet hovering hungrily over them.
If both parties have pets, these pets may well act out the same scene on each other in a more comical/animalistic manner.