Re: Why would you want to hurt your supplier?
There are different types of commercial relationships.
Some of my suppliers are very simply 'transactional' suppliers who add little value over and above that which another similar supplier could easily do. In this case, my relationship with said supplier is about cost, efficiency and reliability - classic SLA stuff and everyone knows the rules of the game.
Other suppliers are true partners. These suppliers are adding value to my business through their skills, knowledge and capability. True partners will look not just at the project or operational objective, but at the business outcomes and work toward making those come about.
Then there are companies in the middle of the two extremes, and to me these are the ones at risk. They're not efficient and they're not strategic. They're opportunistic - and when you're living from opportunity to opportunity life can be perilous.
I certainly wouldn't want to 'hurt' my strategic partners - rather, I'd expect to tie their commercial success to my own commercial outcomes.
I don't have the need to 'hurt' my transactional suppliers - we can easily move around there, so there's a natural inclination from those guys to keep me happy enough.
Where I do like to ensure that I get best value is from the opportunistic supplier - things I do as one-offs. However, even then I prefer to ensure that I have a viable way of supporting and maintaining those things as needed, so I prefer even my opportunistic suppliers to prove to me that they're around for the long haul. Otherwise, all I am doing is buying a big bag of risk.