Buddhism is a path of profound simplicity. It doesn't require religious belief; it's a psychological practice that can be tested via our own experience.
I guess one could summarise it as being about waking up. The heart of Buddhist practice is to do with weeding out whatever it is that gets in the way of the flow of love, understanding and wisdom, of our alignment with essential nature.
The Buddha spoke of our suffering as being largely to do with the 'three poisons', or obstacles that get in the way of our living in an enlightened way: greed, or attachment/craving (whether to people, situations or, for instance, our own opinions, likes, preferences, or getting our own way); hate, or aversion (to people, situations, aspects of life that don't suit us); and delusion – an unwillingness or inability to see true nature, essential reality, exactly as it is, to truly see into the heart of things.
This makes good psychological sense; startlingly insightful and revolutionary in many ways, especially given that it is as relevant now as it was when the Buddha, Siddhartha, was alive nearly two and a half millennia ago.
In a culture that cannot, on the whole, see beyond the individual ego and its needs, the practice of this examining of what sits between us and waking up usually means heading in the opposite direction from societal norms and materialistic values; like the salmon, swimming upstream.
In the past, a monastic cloistered environment was seen as strongly preferable for doing the work of enlightenment. However, out in the world, engaged with the world, every minute can bring us a prompt to challenge the lazy, fearful, greedy, delusional self-protective ways of the ego.
And the Buddha emphasised that this waking up should not be simply for our own benefit, but for every being's.
I liked this summary of the Buddha's teachings, adapted from againstthestream.org:
The Buddha said his path to awakening was one of rebellion – a subversive path that challenges greed, challenges hatred, and challenges delusion. It is a path of radical, engaged transformation, a path of finding freedom and spending the rest of our lives giving it away.