The character you dislike may have been given the fewest opportunities to explain themselves.

Dislike often tracks exposure rather than character. The figure who gets no interior life, no explanation, no scene from their own side, is easy to condemn, and their guilt can be an artefact of how the story allocated its attention. Understanding is largely a function of airtime.

Apply the test to people rather than characters. When you find someone difficult, ask how much of their reasoning you have actually heard, and from whom. Often the answer is very little, and most of it secondhand. Giving someone one uninterrupted account of themselves is a small experiment, and it changes the verdict more frequently than you would expect.