Forcing positive thinking puts us under pressure and in an always-on-the-alert mode. We can never relax because a negative thought might pop into our heads when we least expect it.

It can make us feel more negative emotions and we may blame ourselves for not being happy enough.

Emotions like fear and anxiety can help us to act in certain situations, for instance, alerting us to danger. Anxiety should not be avoided. It can point to an underlying issue that needs to be addressed.

Thinking negatively can also help us prepare for worst-case scenarios in advance. How...

Positive affirmations can actually be detrimental.

If you have low self-esteem, repeating feel-good phrases can make you feel worse. And for those with high self-esteem, although positive affirmations tend to improve your mood only slightly, there's no lasting effect.