I like looking at things with the full picture. Sometimes, there are positive aspects. At times, there might be some negative things. If you only see one side of a story, you’ll likely make errors due to too much pessimism or optimism.
Too much optimism makes you overconfident and makes mistakes of the sort – “I trust myself too much”. If you don’t see the bad side of things, you’ll likely do wrong things.
Too much negativity and critical thinking can affect your mind, but can also lead you to wrong decisions. For example, if you only read news via social media, you’re likely to have a negative opinion of the things around you.