Timna? Who was Timna?
Well, I'm glad you asked. Here's the answer, courtesy of Sanhedrin 99b:
Timna was a royal princess, as it is written, alluf [duke] Lotan, alluf [duke] Timna... Desiring to become a proselyte, she went to Abraham, Isaac and Yaakov, but they did not accept her. So she went and became a concubine to Eliphaz the son of Esau, saying, ‘I had rather be a servant to this people than a mistress of another nation.’ From her Amalek was descended who afflicted Israel. Why so? — Because they should not have repulsed her.When someone is distanced from the Jewish people and made to feel unfit, the consequences can be disastrous. Timna was turned away three times, once by each of the holy Patriarchs, when instead they could have welcomed her with kindnees and taught her the ways of God. The result of their brutality was Amalek, eternal enemy of the Jewish people.
Keep this in mind the next time you're ready to sneer at someone who doesn't wear a hat, or similar.