Assumptions!
We all make them. We must make assumptions, on many different levels, just to get through the day. Yet assumptions can be very limiting, when we forget that we're making them.
Making assumptions can hinder communication, such as when you assume someone understands what you're talking about, and they don't. Assumptions can limit creativity, when you dismiss ideas with a hasty "that'll never work."
Here's an assumption that will neutralize assumptions -- assume the preposterous. For example, assume that it would be bad to get more new business, and then look at the reasons why. What you learn might improve your profits.
Remember that behind every judgment you make, there are assumptions. What are yours? The same old assumptions, often lead to the same old results. To break new ground, break free of your old assumptions. Challenge them, flip them around, turn them upside down, and you'll see many new, exciting possibilities.