Expensive decision

This spring one business owner shared a story about a VOIP system installation. Wrong vendor, wrong application for vendor to install, wrong dollar spent on wrong application for customer. Or was this the wrong application and the wrong vendor or just ignorance on the vendors part. Installations without a lot of questions with answers from more then the decision maker is the first sign of a lack of thorough analysis. Sales people are great but how often do they ignore the needs, applications, culture, departmental workings, internal department as well as external customers need? Some and take all the information from the decison maker and they may be smart but they know everything while there doing their responsibilities?