Making money is essential in order not to be unhappy. 

The best way to make money is giving high quality service.

If we keep our focus on making lots of money
we may loose the attention we give to rendering high quality service
and end up loosing clients and money very fast.

If  we keep our focus on making lots of money
we may introduce some unfair practices in our service
which may make more money but will not last 
and be only a source of worry, stress and anxiety.

So it is best to keep our focus on good service
Good service is by far the best way to make good money
It not only will make us feel good about the money generated,
but satisfaction, peace of mind and true happiness
are unavoidable consequences of rendering high quality service.

So, yes,
Rendering high quality service is among the essential
... ingredients of happiness