Due to karmic influences, the world appears in different ways to different people. When a human being, a god, and a preta (hungry gost) - three sentient beings - look at a bowl of water, the karmic factors make the human being see it as a water,
while the god sees nectar and the preta sees blood.

The reason why we find so much discussion of epistemology, or how to define something as a valid cognition, in Buddhist writings is because all our problems, suffering and confusion derive from a misconceived way of perceiving things. This explains why it is so important for a practitioner to determine whether a cognitive event is a misconception or true knowledge. For it is only by generating insight which sees through delusion that we can become liberated.
Even in our own experience we can see how our state of mind passes through different stages, eventually leading to a state of true knowledge. For instance, our initial attitude or standpoint on any given topic might be a very hardened misconception, thinking and grasping at a totally mistaken notion. But when that strong grasping at the wrong notion is countered with reasoning, it can then turn into a kind of lingering doubt, an uncertainty where we wonder: "Maybe it is the case, but then again maybe it is not". That would represent a second stage. When further exposed to reason or evidence, this doubt of ours can turn into an assumption, tending towards the right decision. However, it is still just a presumption, just a belief. When that belief is yet further exposed to reason and reflection, eventually we could arrive at what is called 'inference generated through a reasoning process'. Yet that inference remains conceptual, and it is not a direct knowledge of the object. Finally, when we have developed this inference and constantly familiarized ourselves with it, it could turn into an intuitive and direct realization--a direct experience of the event. So we can see through our own experience how our mind, as a result of being exposed to reason and reflection, goes through different stages, eventually leading to a direct experience of a phenomenon or event.
Dzogchen: The Heart Essence of the Great Perfection

In the realm of matter, one and the same object can serve as a cause of happiness for some living beings, and a cause of suffering for others. Certain plants, for example, function as medicine for some creatures, but for other species they can be poisonous. From the point of view of the object itself there is no difference, but because of the physical constitution and the material state of the particular living being, that single self-same object can affect them in different ways. Then, in the sphere of our own experiences, the same holds true. A certain individual may appear to some as very friendly, kind and gentle, and so gives them feelings of happiness and pleasure. Yet to others that same person can appear harmful and wicked, and so cause them discomfort and unhappiness.
What this kind of example points to is that, although external matter may act as a cause for our experience of pain and pleasure, the principal cause that determines whether we experience happiness or suffering lies within. This is the reason why, when Buddha identified the origin of suffering, he pointed within and not outside, because he knew that the principal causes of our suffering are our own negative emotions and the actions they drive us to do.
Dzogchen: The Heart Essence of the Great Perfection

When we say that the ignorant mind is perverse or wrong, we are talking about the way it misconceives reality. Now the pertinent questions are: What is reality? How is this mind mistaken about reality? And in what way does the mind wrongly apprehend reality? Reality or emptiness of true existence is something that can be established logically. There are sound, or perfect, reasons to prove the emptiness of inherent existence, and we can gain conviction in these reasons. On the other hand, there is no logical way to prove true existence. True existence is what appears to an ordinary, untrained consciousness. But when it comes under logical scrutiny, true existence cannot be found. Even in our everyday life we often find contradictions between the way certain things appear and their actual mode of existence; that is, the way things actually exist is different from the way they appear to exist.
...Our perception of impermanent things like mountain ranges and houses does not conform to their actual mode of existence. Some of these things have existed for many centuries, even thousands of years. And our minds perceive them in just that way--as lasting and permanent, impervious to momentary change. Yet when we examine these objects on an atomic level, they disintegrate every moment; they undergo momentary change. Science also describes a similar pattern of change. These objects appear solid, stable, and lasting, but in their true nature, they constantly change, not keeping still even for a moment.
Stages of Meditation