To dream that you break something, like a window or a chair, indicates that changes lie ahead and that you want to change the direction in which your life is heading. Alternatively, it suggests that you need to take things more slowly.
If you drop or smash things in your dreams, this indicates that you are letting go of—or need to let go of— some project, relationship, person or idea. Be sure to analyze the significance of what is being dropped or smashed. Another explanation for dreams of breaking things is that you are expressing some dismay or regret at how you let something slip through fingers.