Do not let your love be obsessive and do not let your hatred be destructive. When you love, do not go to a level of obsession as a child does with the things he loves, and when you hate, do not hate in such way that you want your opponent to be destroyed and doomed.

Umar Ibn Al-Khattab رضي الله عنه
(Narrated by Abd ar-Razzaq in al-Musannaf)