In the Buddhist philosophy that I follow, it is thought that human suffering is the result of the cyclical reliving of behavior patterns. The human condition is said to be one of both quiet and overt suffering, because we are trapped into repeating the same behaviors again and again. For very fundamental Buddhists, this is believed quite literally——that the human soul/personality is actually reborn again and again in subsequent lifetimes. For Buddhists of a more symbolic bent, it's taken as a comment on our human habit of reliving the same behaviors and problems again and again within this life.
Either way, though, the driving mechanism of this literal or figurative rebirth is the energy of hunger, hatred and ignorance. The cyclical, recurring problems of our existence arise because because we don't see things as they are (ignorance), which leads to either some form of subtle or obvious longing or attachment (hunger), or some form of resistance and aversion (hatred). These three problems are very intimately connected, and making progress on one leads to progress on all three. In other words, seeing things as they are quite naturally causes a reduction in grasping or aversion, and reducing grasping will naturally lessen hatred and cause us to see things more nakedly.
The principle tool of spiritual development, for Buddhists, is meditation, and the goal of meditation is quite simple: to practice the surrender of our pulling and pushing, our hatred and hunger, and thereby see things as they are. Should we ever accomplish this permanently, the legendary result is nirvana——the escape from the dreariness of cycle repetiion. Fundamentalists believe that such a soul no longer requires rebirth; more modern believers suggest that such accomplishment will cause this life to be one of peace and happiness.
To the westerner approaching Buddhism from a different culture, all this will feel pretty alien and unnatural, but very gradually almost everyone who steadily practices will see some literal truth to it. Most of us see it only in small glimpses, especially at first, but it is surely there: surrendering aversion and grasping causes you to see things much, much differently, and the result is a peace of mind that is most definitely transcendent and can be life changing.
Buddhist practice can seem to be a bewilderingly complex system of practices and lessons, but it's important to understand that it is all really about this very simple goal of surrendering hatred and longing, and seeing phenomena as they are rather than through the filters of wanting and disliking. Although there are many different schools of Buddhist practice, they all share this goal. The practices that focus on seeing the impermanence of phenomena, for example, focus on this because it automatically shows you that there is no logic to clinging to things that will vanish in a moment. Practices that focus on non-selfish compassion for others are designed to lessens our attachment to ego. The "middle way" that is so much a part of Buddhist practice is largely about applying antidotes to the extremes of greed and hatred in an effort to find the silence that occurs when they are neutralized.
On a very practical level, I have found that there is a tangible physical sensation to this surrender of longing and aversion. At meditative moments when I momentarily know myself to be in the zone, there is an almost cellular sensation that an energy which normally grips us, like magnetic charges either attracting or repelling, suddenly falls silent. The feeling can be a bit unnerving and ungrounding, and can even frighten you at first. But if you can come to trust it, you find a delicious sensation of peace and calm within it. A frantically spinning hamster wheel suddenly falls silent. I think that my own practice, whether it involves one lifetime or many, will be to gradually trust this sensation and rest comfortably in it more and more often.
And progress doesn't require any kind of massive accomplishment, but rather just an ongoing surrender of the habits that interfere.