The Say-No promise is a core tenant of Appropriate Additive Manufacturing. That means, sometimes I say no, even when it doesn't benefit me.
I was offered a large 3d printing project, from which I was given a deposit to order oversized spools of ABS (10kg - big). I then did a full model review, of a cart and realized: While I can make this prototype, this product is not appropriate for the job it is intended. I am working on a car, and it has 600mm*2 held up by a live hinge. This was obviously going to sag and maybe break. So, I voiced it.
I printed a 1/5th scale sample to voice my concerns, so there was no doubt this would not do the job it set out to intend.
This could have been a slam dunk print for me, and paid for full uptime on my AON M2+ printer, my largest and most expensive of the fleet. I was charging 1/10th of another company, and due to my fleet produced a better item.
Now, it is in limbo, all because I said no before the person had thousands invested in a NO.
This is what good partners should do, even if it hurts them.
I get calls frequently asking for different technologies, MJF, SLS, SLA, LPBF, PolyJet(a lot of PolyJet people requests).
I send these people to the appropriate place, I could profit giving them substandard parts very often or scanning them to transition to a process they would not want to pay for.
I get a lot of chances to do for me first and foremost, and I always say No. I know for a fact other's won't.