Don't take anything personally. Nothings others do is because of you. What others say and do is a projection of their own reality, their own dream. When you are immune to the opinions of others, you won't be the victim of needless suffering. (Don Miguel Ruiz, from the book, The Four Agreements)
This one is a bit of a challenge, as we tread a fine line between respecting people by taking them seriously and respecting ourselves by clearly knowing that they are merely expressing their own reality, not ours. It takes practice! But every time you succeed, even just a little, you have added to your own serenity and happiness.