Critical thinking refers to the ability of human beings to make balanced and assertive decisions. With that, we can say that critical thinking must go hand in hand with rationality and our ability to analyze and evaluate situations in a rational way, without taking into account the emotions that these situations can trigger.
Emotions, both happy and sad, hinder rationality and consequently hinder critical thinking. With that, when we are happy we can make inconsequential decisions based on impulse and positive thinking. This type of emotion does not allow us to evaluate the results of our choices, nor even to analyze whether we are acting correctly. Sad emotions, on the other hand, detract from the quality of our choices and we end up making inefficient, weak and insufficient decisions that cause negative results.
An example of when a positive emotion damaged my critical thinking occurred when I was very anxious for the release of a book I wanted and ended up buying it as soon as it was released, since I was very happy. I was unable to reason that I could buy this book at a lower price after the release period, which would help me save money.