The intention as to weather to hurt, correct or just have fun might be at issue in regards to sarcasm. My wife say I'm "nuts, but screwed on the right bolt". That seems endearing.

Jesus used sarcasm to make a point (John 10), and so did the prophet Micaiah in 1st Kings 22. I admit I use it while preaching, especially to show the folly of sinful practices that are being dumped on the public as "alternate lifestyles", "outcome based education" or "freedom of speech".