Why do I react to others' opinions about me?
The basis of our reactions is insecurity.
Since childhood, we have been conditioned to compare ourselves with others. Our parents and teachers have constantly set benchmarks for us. These benchmarks are in keeping with the norms and conventions of society. We judge ourselves according to these norms and thereby lose our individuality. We become dependent on what society terms as normalcy.
What is normal for one may not be normal for another. Normalcy is relative. For example, if we try to adopt an ancient philosophy to our current life, it may not suit us because it is someone else's philosophy and belongs in a different era.
If you were to look at the moon, where would you seek it? In the sky, of course! Not in a 'pond' for it's reflection. The 'pond' is somebody else's view and opinion. Look in the sky; do not react and do not be a puppet!