Incomplete Data is Misleading

• Broader categories are always more probable than their subsets. It's more likely someone has a pet than they have a cat. It's more likely someone likes coffee than they like cappuccinos. The extension rule in probability theory thus states that if B is a subset of A, B cannot be more probable than A.
• Likewise, the probability of A and B cannot be higher than the probability of A or B. It is more probable that Linda is a bank teller than that she is a bank teller and active in the feminist movement.

A plan is like a system. A change in one component of a system will likely impact the functionality of other parts of the system. 

The more steps involved in a plan, the higher the chance that something will go wrong and cause delays and setbacks. For this reason, home remodeling and new product ventures seldom finish on time.