It is considered acceptable behavior in many circles. “Yeah, I’m kind of mean, but that’s just who I am,” might be one person’s reasoning. Another has been known to say, “Well, we live in a mean world. 
Everyone is mean, so you have to be mean to survive.” What does God say?
There is much in Scripture on this topic, but consider just these few words from Romans 1. God identifies several individuals, at the end of Romans 1, who have no favor in His sight. He calls out those who are “whisperers” or “gossips” (v. 29)–ones who speak secretly into another’s ear. He censures the “backbiters” or “slanderers” (v. 30)–ones who speak out disparagingly against others. He denounces the “insolent” (v. 30)–ones who are arrogantly rude, insulting or disrespectful. He warns the “proud” or “haughty” (v. 30)–ones who set themselves above others and are “stuck up.” He admonishes the “unmerciful” (v. 31)–ones who are ruthless in their treatment of others. Then He announces that “those who practice such things” and also those who “approve” of the practice “are worthy of death” (v. 32). Wow! That’s a big deal!
“Kind of mean”? What an oxymoron! In God’s dictionary, the two words are poles apart!