• Blindsided by problems:  Often this comes from making mistaken assumptions about situations.  In my own case, I mistakenly assumed I could recover from my computer and Internet problems faster than was reasonable to expect.  I also assumed that I would have more Internet access during my vacation than I actually had.  What will I do differently?  I’ll build in more checkpoints to assess what’s happening and contingencies to use for this type of “predictable emergency.”
• Continuously in “firefighting” mode:  We all have the occasional urgent and important issue to handle, but I’ve found that when firefighting becomes the norm instead of the exception, it’s usually because of mistaken assumptions at the planning stage about the practical aspects of the plan, such as your own and others’ priorities and resources to get things done. This is especially true when an individual or group is making many changes at once and trying to meet more commitments than is realistically practical in that time frame.
• Good plans grind to a halt:  While this turn of events may seem mysterious, the reasons can often be traced to a series of overlooked and/or underestimated assumptions about stakeholders, such as mistakenly assuming that you and or others have the commitment, knowledge, skills, or abilities to implement the plan.

Just as with assumptions that do serve us well, the key to catching assumptions that don’t serve us well is to recognize which aspects of our situation are based in fact and which are based upon values, beliefs, and attitudes that are strictly in our minds. 

Ultimately, we must make assumptions in order to grow and move forward in an uncertain and constantly changing world.  They key is to be accountable for this type of thinking, and to realize that using assumptions wisely is as much an art as it is a science.