The actual word is “dukkha”. It’s sometimes translated as suffering. However it is more generally unsatisfactoriness. Sometimes as “stress”. But none of those really capture its meaning. What if you are experiencing nothing but happiness, a life of pure joy? Is that not possible? It would certainly be a life without suffering and without stress, and most would say, a life without any unsatisfactoriness either. If you asked someone who is experiencing nothing but pure joy for years on end, if any such people exist - would they say their life is unsatisfactory? Probably in most cases they would say “What are you talking about? Everything is great. My life is very satisfactory!”. Would that not be a life without dukkha?

Well - not really. Because however much pleasure and joy you have in this life, at some point your situation will change. The things you enjoy will be gone. The people you were friends with will be no more. Eventually you will die yourself.

We all know this. Buddha himself, according to the sutras, found ways to rest in very subtle states of mind from his teachers Alara Kalama, and Uddaka Rammaputa. But he decided that this wasn’t what he was looking for, that these teachings, though they lead to such refined states of mind, did not lead to the cessation of dukkha.

What if he had followed through and done those meditations for the rest of his life, and experienced nothing but pleasure, and more refined states even than pleasure, perhaps even for the rest of his life? Would that not be freedom from unsatisfactoriness? Well - not really.

Example, the pleasure you get from eating chocolate. However much you enjoy it, you can’t solve all your problems and reach permanent happiness by eating chocolate. If you feel that this is the solution to your problems, to eat as much chocolate as you can for the rest of your life, well that’s not going to work is it? You’ll soon get tired of chocolate, or eat so much you get sick, and then you have to find something else to find pleasure in.

So there is an unsatisfactoriness about it. Not really intrinsic to the chocolate. It’s more to do with the way we try to find a permanent happy place here in a world which is continually changing.

So, it was the same with these refined states of mind he found. That they did lead his mind to calm, peace, but it was not a permanent solution, no more than eating chocolate is. Was a peace that was much more long lasting, indeed maybe even after this life he’d have ended in a state without any body, just mind, calm peaceful mind, for trillions of years. Even if that was true, still, he concluded, that at some point the conditions that lead to him experiencing this would exhaust themselves, just as happens with the pleasure of eating chocolate, though not so immediately and not so easy to see - and then he’d be on to the search for the next way to find pleasure or peace of mind.

So - that’s what the teachings on dukkha are about. And the pleasure is good. Being happy is good. Indeed the Buddhist path is a path to happiness. Happiness for yourself and happiness for everyone else. But it’s a happiness not based on trying to make a permanent happy home in the changing world, but on relating in an honest direct way with the impermanence.

This is how Walpola Rahula puts it in "What the Buddha Taught", in his exposition of the first truth which is also what all the teachers I've heard have taught:

“First of all, Buddhism is neither pessimistic nor optimistic. If anything at all, it is realistic, for it takes a realistic view of life and the world. It looks at things objectively (yathābhūtam). It does not falsely lull you into living in a fool's paradise, nor does it frighten and agonize you with all kinds of imaginary fears and sins. It tells you exactly and objectively what you are and what the world around you is, and shows you the way to perfect freedom, peace, tranquility and happiness.”