Final answer:
A hissing cat is a clear warning sign, while purring and kneading typically indicate positive emotions but can also signify anxiety and pain, respectively. A fast wagging tail may indicate irritation or overstimulation, and raised fur is a sign of a cat trying to appear threatening.
Step-by-step explanation:
Understanding the behavior of animals, such as cats, is important in identifying their mood and intentions. When it comes to cat communicating a warning, certain behaviors are indicative of discomfort or irritation. Hissing is a clear sign that a cat is warning someone or something to stay away. It's a defensive behavior used when a cat feels threatened. In contrast, purring is often associated with contentment and comfort, but it can also occur when a cat is in pain or anxious, so context is important. Kneading is another behavior that typically reflects a positive emotion; it's something cats do when they're feeling relaxed and content. Lastly, a wagging tail can mean different things depending on the motion, but if it's a fast, thrashing wag, it can be a sign that a cat is irritated or overstimulated.
It should be noted that cats will also raise their fur to appear larger and more dangerous as a way to discourage predators or threats, a trait shared with many mammals. The key takeaway is to observe the full context of a cat's behavior, not just one signal, when interpreting their communication.