[yeraydarias]

There is another problem. The uncertain future.

When you start using a NoSQL solution it can be nice and fit the problem quite well. Then the solution gets bigger, new features appear and new data is stored, but the storage is NoSQL. With the solution getting bigger some business intelligence could be required by marketing or other people in the company. But we all know that NoSQL solutions aren't so good with aggregated queries, but in the rush it is hard to slow down to create a second solution for this kind of queries.

So, yes, you are right when you say "People not understanding what NoSQL is good for and when to use it over relational". But the main problem is that you don't know the complete problem in advance usually.