A cat doesn't need much to be happy. Give it food, water, a place to sleep, and some affection, and it will be grateful for your care. Humans, on the other hand, are constantly stressed about things that are not necessary for our well-being or survival. All of this stress takes a toll on our mental health, and we end up valuing things that we don't need, but are taught we need.
We learn that the ideal life is one of wealth, social activity, and a good formal education, that these will give us long-term satisfaction. But, a cat doesn't need any of that, so why do we? Of course, our needs are different from those of felines, but beyond the necessity of money, we could just as well live in a small apartment with little else and learn from them the easier, more cost-effective path to happiness. Once we have learned this, we can start applying it to our own lives.
Cats are generally solitary creatures, even though they can enjoy some interaction with us. You won't find them arguing with you, accusing you, or threatening to sue you. Perhaps our social nature is the root of most, if not all, of the drama and opression in our lives?
There is also the pressure to impress others. Cats don't need to boast about their accomplishments, as they are small creatures and seem to know it. But for some humans, the thought of being in a lesser standing is very stressful, as it would mean that they are "less" than those who enjoy higher pay, social status and so on. The truth is, there is no need to impress anyone unless you truly have to, and there is no shame in enjoying a life of relative simplicity.
It isn't easy to feel like we have to prove our worth all the time. I also feel compelled to do so. But when I see my cat finding great satisfaction in being pat and nothing more, I sometimes wish I would've been as satisfied as he.
Finally, the core difference between cats and humans is that cats are unable to philosophize. Philosophizing can be used against ourselves when we doubt the necessity of our existence in this universe, like when asking ourselves if we should resume existing.
Cats, on the other hand, do not care about such existential matters. They spend much of their lives sleeping and do not care whether the day has been productive or not, or whether they are wasting their lives doing nothing. The whole element of having to prove something to both themselves and others is forever absent in their minds. As such they may live and love unconditionally. The only conditioning for their life is that of every other mammal. The same conditions the ascetic lives by.
This is why cats teach us that we should consider staying away from all the stressful loops we put ourselves in, because in the end, these loops have little meaning in relation to the attainment of happiness. At best, the "rat race" of life should be limited to finances. Other than that, see for yourself how easy it is, once mastered, to put the existential and social burdens aside and just exist, with little severity.
As for myself, I have little reason to exist beyond writing. Seeing the enjoyment of my cat over little things, writing is the only thing in life that I aim to treat with true zeal. The rest matters little, or at least should matter little. I just want to work and finish the task that is my life. I see little reason for anything else.