Someone quoted to me a Gemara in Sukkah which said that Hashem had charata that He created arabs. What daf in Sukkah is that on?
The source is Sukkah 52b:
אמר רב חנא בר אחא אמרי בי רב ארבעה מתחרט עליהן הקב"ה שבראם ואלו הן גלות כשדים וישמעאלים ויצר הרע ... ישמעאלים דכתיב ישליו אהלים לשודדים ובטוחות למרגיזי אל לאשר הביא אלוה בידו
Rav Chana Bar Acha said a saying of the school of Rav (it is debated what that is a reference to - see the link) The Holy One Blessed be He regrets four things, Exile, Kasdim, Ishmaelits and the Evil inclination ... Ishmaelites as it says "The tents of robbers prosper, and those who provoke G-d are secure, to whomever G-d brought it with His hand." (Iyov 12:6)
Rashi explains that the "tents of robbers" means the tents of shepherds (shepherds are often viewed in Chazal as robbers because they let their flocks graze on other's lands) and the whomever G-d brought it, means that G-d provoked His own anger, so to speak, by bringing them into the world.
Sukkah 52b Hakodosh Baruch Hu regrets creating 4 things. One of them is Yishmaelim.