When you are anxious or fearful, your visual perception narrows and sharpens. You become more sensitive to contrast. Because your emotion is priming your brain for threats.
This also happens when you perceive these emotions in other people. It starts before you're consciously aware that someone else's face IS showing fear.
Conversely, we have broader visual scope when we're happy or joyful. Especially when there are distractions around. That applies whether our joy was primed by a psychological experiment, or coincidental.
Of course, I'm not really interested in your powers of visual searching. But I hope that this has illustrated that even something fairly simple (your vision) is influenced by your emotions.
Broadening your perception
Now think about other things you can see - like options that are available to you, or other people's perspectives.
The same holds true. When you are in an anxious or fearful state you don't see as many options as when you're happy. And you are less likely to consider other people's circumstances and feelings. Even in exactly the same, experimentally manipulated, circumstances.
This applies across your life, and is determined by where you choose to place your attention.
People who spend more time, on average, attending to positive stimuli than negative have broader perception. Their world is bigger than the world the rest of the population inhabit.