Cat vs. Dog Body Language Differences
The same signal can mean very different things depending on the species, which is one of the most common mistakes new sitters make.
A wagging tail means excitement in dogs but often means irritation or overstimulation in cats. Dogs often welcome sustained eye contact from someone they trust, while cats usually read direct eye contact as confrontational. Even a slow blink from a cat is closer to a sign of trust than a stare is.
When in doubt with any animal, let it set the pace of interaction rather than assuming your read on the situation is correct.