If we're talking pure biology, one of the reasons people want to be loyal is that it allows them to reduce their choices and essentially save their brain power for other things in their life that may demand more thought.  

For example, when you make a trip to the grocery store, there are some things you spend time investigating (like making sure that the fish is fresh and the fruit isn’t too ripe), and others that you simply throw in your cart without a second thought (salt, butter, eggs, etc.)  It’s our brain’s way of making us more efficient and simplifying our lives. Evolution has taught us to focus on the variables - the things likely to change - and blindly accept what has proven to be consistent.  

The freshness of fish, beef, or chicken is a variable that could have dire consequences for us - from the simple (our food tasting nasty) to the dangerous (being poisoned and spending the night in the hospital) - so it is in our best interest to spend the time evaluating its quality. Salt, on the other hand, is predictable. There is no risk to choosing exactly the same brand we always choose, so we accept it as a shortcut.

Our brain chooses the relationships in our life much the same way. Those people who have proven themselves to be consistent  - who offer real value without any risk - make our lives easier. We are loyal to them. But those who are unpredictable, who are a drain on our brain power and require us to be constantly cautious and on guard, they are the variables. Just consider all the people that are variables in your life. The people whose work you need to constantly review, the people who have their own agenda different than yours, the people whose actions are potentially dangerous to you or your organization. They are the ones who take up so much of your time and energy and distract you from the things you would rather be doing. 

Now ask yourself: Am I a variable employee?  Am I a variable manager?  Am I a variable client?  Do I make the lives of the people I work for and the people who work for me easier or am I someone they have to spend valuable time worrying about because they are never quite sure how consistent I will be? 

James Kane