There's a dreaded human condition that as we business consultants see all to often. 

The fizzle factor is when clients willingly spend a lot of money with you, implement and learn what you instruct them in, get great results, but soon after the consultancy engagement is over and the consultant is no longer in the business keeping an eye on things, the client engagement starts to fizzle.

Soon enough the client "forgets" the great leaps and results they were getting with the changes that were implemented and soon enough the client begins to reap the same mediocre results the client used to get before the consultant came and showed a better way.