Or "something bad"?
We're talking Lenten sacrifices, of course.
I've heard people debate this, but I see no reason to debate. We don't have to punch it out over this one. We just have to figure out the answer to this question: "Will it help me grow closer to my God?"
On the rigid definition side, we have those who say that we must give up "a good" or else it really isn't a sacrifice, a sacrifice being the giving up of an objective good for a greater good.
On the loose definition side, we have those who say that giving up "something bad" (a bad habit, such as complaining, or smoking) is just as difficult (if not more so) as giving up something good, and therefore, it can be a great spiritual exercise.
I declare a draw. Both sides can be right.
The key is in our perception: if it's tough to give it up, it means we're inordinately attached to it. Ultimately, does it matter if the thing we are attached to is "good" or "bad"?
In one sense, no. It's the giving up of the attachment, for God's sake, that counts. By giving up our attachments and our addictions, we're saying to God, "You are more important to me than this thing. I'm giving it up for You."
Whether that thing is smoking, or complaining, or another addiction, doesn't really matter. It's the act of love that counts. And, our act of love often leads to real behavioral change. When we give up an addiction for God, we open ourselves to grace, and find Him working on our hearts, ridding us of painful, controlling attachments.
In that sense, it's certainly an acceptable Lenten sacrifice to give up "something bad."
On the flip side, if we give up something that is objectively good, we get the joy of that thing's return on Easter Sunday. And this is a beautiful thing to experience. We see, in a small but concrete way, what it means that sacrifice leads to Resurrection. (As I wrote in this essay, "Break out the chocolate bunnies! He is Risen!")
There's still room for debate: is chocolate an objective good* or an unhealthy addiction? What about alcohol (in moderation, of course)? Blogging? Meat every day? Desserts? TV and movies? Music?
So often, there is overlap. Are we addicted to what would be, in moderation, an objective good? Perhaps, come Easter, we'll find that God has helped us to let go of the attachment, and enjoy the thing as it's intended to be enjoyed. There's nothing wrong with dessert. God invented sugar. But He didn't mean it to be the mainstay of our diet. (That overlap is why I often choose several things to give up -- something in the "Help me get rid of this forever, God" category, and something in the "Break out the chocolate bunnies" category.)
It's all so personal. What's easily managed for one person is a torturous attachment for another. That's why we can't really debate about the "right things" to give up for Lent.
If giving it up will help you grow closer to God, then it's the right thing for you.
*Okay, so this one is not up for debate. God invented the objective good of chocolate right after Adam, Eve and children.