A leap of Faith

I think it's time for a little rant.
Just a little one, and not really a bad one.

Did you know there are "trust issues" of a different kind?

Sometimes, people trust someone too much, or trust them on the wrong plane so to say.

I do a lot of comission work. Therefor I have to communicate with customers on a multitude of different planes.
About motivs (of course), techniques, sizes, and colour range.
Usually my customers trust my opinion. I offer different techniques, suggest colours, sizes.
When I'm told the motivs or see the photos of which I am told to make a portrait I can tell what would be the best technique etc.
And my customers trust me.
That's good.
Sometimes my customers have more faith in my skills than I have. Sometimes they have too much faith.

From time to time I hesitate when it comes to difficult motivs and it's pretty nice to have someone tell me "I trust in your skills, you can do it!"
But there has to be a line.

Lately I had several customers whom I told that I couldn't do the requested paintings with the material they offered. sometimes the photos were too bad, sometimes the research was incomplete....
In those moments I stand there and tell them "I can't do it with that data." or "those photos are nice but they won't do as a painting."
And my customers tell me "I trust you, I have faith in you."
But faith has nothing to do with it.
They trust me and my skills but aparently they give a shit about my professional opinion.
Recently I had such a customer "overpower" me and the result wasn't that nice.
The comissioned work turned out okay but we had some majour difficulties. ending in dissolving the contract.
So now I am more careful.
And I stick to my standarts, even if that means that, from time to time I have to decline a comission when the data doesn't suffice.
I just wonder; why do these people listen to me when I explain techniques and used colours but completly ignore me when I tell them; the better the data to work from the better the outcome?

I guess I'll never get an answer...