A common theme in Buddhist practice, including Zen, is what the earliest texts call 'dukkha'. The most common translation of this Pali term is 'suffering', but sometimes that word doesn't work so well for people - it can come across as pretty drab and heavyweight, like you need to be living in a Greek tragedy in order to qualify. A more modern term that's become quite popular is 'stress', but that comes with some other connotations and can make the whole thing sound a bit like a psychological therapy, which isn't quite what we're getting at in Zen. Personally, I quite like another term that I first encountered in the Chan (Chinese Zen) tradition - 'vexations'. From time to time, we all get vexed. We can all think of that one person who's... well, vexing.
People come to Zen practice for a variety of reasons. One common motivation is an excess of vexation: they find, for whatever reason, that life just isn't really working for them, and they want a way out, something to alleviate the suffering. This is the Buddha's own story: he looked at what life had in store for him - old age, sickness and death - and decided he didn't fancy it much, so set off to explore the spiritual path and see what could be done about it.
Not everyone comes to practice through being excessively vexed, of course. For some people it's more about curiosity, a sense of exploration, of wanting to know what's going on - this meditation thing seems to do something, but what? What do these cryptic texts actually mean? (That's been my primary motivation for practice.) And, of course, there are many other reasons too.
Whatever the motivation to practice, however, sooner or later we run into vexation and have to learn to deal with it. The mind spends a lot of time bouncing from one vexation to another, driven by preferences - a process of categorising our experience into things that we like (and hence want more of) and things we don't like (and hence want to get away from). This process is so deeply ingrained that it actually colours our very perception of the world, making the good things appear more attractive than they are, and the bad things more repulsive. So we're being constantly pushed and pulled around by these preferences, with the mind rarely given a moment's rest.
Allowing the mind to come to rest is an interesting experience. When the mind becomes still enough, we can temporarily drop the preferences colouring our perception. When that happens, we see 'things as they are', to use the traditional phrase - this moment appears to us without any sense of lack or insufficiency, any sense that it needs to be in any way different. This sense that things are fine just as they are, of wishlessness, develops into a feeling of profound contentment, a deep source of inner well-being which is not at all dependent on anything outside of ourselves. Sometimes in the Zen literature you'll see descriptions of reality appearing as spontaneously 'perfected' - perfect not in the sense that it glows and shoots rainbows, but in the sense that we truly experience the world as not needing to be different in any way, but rather to be completely and wholly fine just as it is - in other words, perfect.
So this gives a sense of one way the path of Zen can unfold. We begin by understanding what gives rise to vexations; only then can we begin to learn how to be free of those vexations. And then as the mind progressively lets go of vexation and settles into stillness, an experience of life that is rich and full, yet fundamentally peaceful and contented, becomes increasingly available to us.
If this sounds interesting, I'd like to suggest a practice that you can use to explore these themes - Zen is first and foremost about direct experience, not about ideas and philosophical arguments. So let's take a look at one way we can explore the mind's tendency to become agitated and see if we can find ways to relax and let go into peace and stillness.
One of the first meditation techniques I ever learnt is called Silent Illumination in the Chan tradition, more commonly known from Japanese Zen as 'just sitting' or shikantaza. In the Chan style, the practice begins by slowly sweeping your attention down the body, from the top of the head to the soles of the feet, relaxing any tension in each part of the body as the attention moves through that region. This helps the body to become still, which in turn helps the mind to become still. The whole process should take at least a few minutes, depending on how long you have to practise. When you've finished releasing tension, you then bring the attention to the body as a whole. The body is still, in a sitting posture; the mind is clearly aware that the body is sitting. And that's it. The 'silence' of Silent Illumination is the stillness of body and mind - whatever comes up (thoughts, sounds, bodily sensations, emotions), we don't get involved with it; we're simply aware of the body, sitting. But it isn't a dull or stagnant silence, a zoning out or switching off. Rather, the awareness is clear and bright - we know very precisely that the body is sitting, and that's the illumination aspect, the clarity which balances the stillness.
That's the basic practice. It may be that as the practice develops (or if you've done this kind of thing a lot already, it might happen almost immediately), it starts to feel a bit narrow and confining keeping the attention on the physical body. If so, it's okay to allow the awareness to expand to take in the whole environment; you can think of the whole environment as 'the body, sitting' and simply rest with that. (At this point the practice is essentially the same as the open awareness practice on the Audio page of this website.) But there's no need to rush to get to 'stage 2' of the practice - whether the focus is on the physical body or open to the whole environment, the skills of silence and illumination being trained are exactly the same. Neither approach is better or worse, they're just different expressions of the same fundamental experience.
Silent Illumination is a very 'complete' practice, in the sense that it develops concentration, insight and equanimity in equal measure, and once you have a taste for the attitude of allowing the mind to be still even in the midst of distraction and activity, you can bring that more and more into daily life, where it really delivers its greatest value. If you're temperamentally suited to this kind of practice it's a great way to go. It doesn't suit everyone, however; some people find that they prefer more 'active' practices such as self-inquiry, for example. As with anything in meditation, it's vital that you explore new practices with an open mind and be as honest with yourself as you possibly can. So give it a try and see how you get on!