Experiences are like trying a new recipe. It might look like it will taste a certain way. We might have heard how other people liked it, but it is only once in our mouth, with the touch of our tongue, that we experience tasting. Now depending on our taste and past experiences with food, we will identify the bite as good, as flavourless, as too salty, as not sweet enough, and so on. Two people could eat the exact same meal and have two entire different perceptions of it.
In the same way, all our experiences are stained by our perception. So if we experience something displeasing, it doesn't mean that its nature is unpleasant it is our perception that sees it this way. With this in mind, we should always doubt our perception. To learn to see things as they are. To get in touch with the true nature of things.