All of us have bad habits. Occasionally, we feel guilty about them. But some bad habits—at least when carried out in moderation—might actually benefit our psychological or physical well-being. Most bad habits alter our mood state and reduce stress (at least in the very short-term) but tend to become less helpful, the more we engage in them. Some of these bad habits turn into addictions, with the short-term benefits outweighing the long-term costs.