Being a Good Client is Important
Conclusion: Better vendors tend to be selective about their clients. Over the years, I have been in many bid-no-bid meetings where it was decided we would not bid for work with a client because the costs and risks of doing business with them was too high.
Good vendors treat good clients like gold. Difficult clients on the other hand often attract two types of vendors - vendors who are not good enough to win business from good clients or vendors who charge difficult clients a hidden premium. Difficult clients can expect low quality service from both types of vendors. Even the better vendors will put their weaker performers on the accounts of difficult clients. After all, why would anyone put good people on a painful and generally low profit account?