Balu Gandhi

Starbucks well understood the rule of thump "if you don't cannibalize yourself someone else will".

If you go to a strip mall where there is a Starbucks coffee shop and a Supermarket, there will be a Starbucks inside that supermarket as well.  These two Starbucks might be few feet apart each other.

Now, Starbucks reinventing themselves with tiny, portable, and hyper local store. The pre-constructed store can be delivered by a truck. http://www.fastcodesign.com/node/1670889

If you are market leader, you have to cannibalize yourself. 

Your commitment to others has to be black and white.  If it's ambiguous, though your intentions are good, it could be misinterpreted by others.

e.g.

I will deliver x, y, and z -  Black and White

I will deliver x, y, and if everything goes well, I may deliver z.  - Ambiguous.