I appreciate sarcasm. I also employ sarcasm, at times when I shouldn't. In fact, when Heather and I first met our small group, there was concern about the integrity of our marriage because Heather and I are prone to freely joking with one another. I began to wonder what role humor and sarcasm should play in my life, if any. I do not believe that God created us to always be dour and serious; rather, I believe that he not only created us to laugh, but that He provides examples in his word of sarcasm.
Consider Isaiah 44:13-18 "The carpenter stretches a line; he marks it out with a pencil. He shapes it with planes and marks it with a compass. He shapes it into the figure of a man, with the beauty of a man, to dwell in a house. He cuts down cedars, or he chooses a cypress tree or an oak and lets it grow strong among the trees of the forest. He plants a cedar and the rain nourishes it. Then it becomes fuel for a man. He takes a part of it and warms himself; he kindles a fire and bakes bread. Also he makes a god and worships it; he makes it an idol and falls down before it. Half of it he burns in the fire. Over the half he eats meat; he roasts it and is satisfied. Also he warms himself and says, 'Aha, I am warm, I have seen the fire!' And the rest of it he makes into a god, his idol, and falls down to it and worships it. He prays to it and says, 'Deliver me, for you are my god!'"
God, through His prophet Isaiah, points out the absolute folly of a man making an idol of wood and in so doing, employs sarcasm. Imagine this carpenter. He takes a block of wood, carving it into an idol and then lights the scraps on fire! I believe God is pointedly demonstrating how foolish this man is.
Although I believe God makes a place for sarcasm and in His perfect design and delights when we laugh, we also need to be cautious with our words. Although words build up and bring joy, they may also tear down.
Psalm 73:8-9: They scoff and speak with malice; loftily they threaten oppression. They set their mouths against the heavens, and their tongue struts through the earth.
God gifts us with language. Words have the ability to entertain, comfort, rebuke, educate, and praise, but they can also harm. Therefore, if we choose to use sarcasm we should be "slow to speak" (James 1:19) attempting to glorify God and love one another consistently.