Recently we building an application for a customer and we had to merge two existing PDF reports into one.
We already have a license for a utility that creates PDFs from HTML web pages. It can also append or merge existing PDFs into its output. But could it just merge two PDFs into one without printing a page first?
Well rather than waste time, our developer asked the vendor via e-mail support. The first attempt got dumped by their spam filter. The second took a few days to generate a response.
In the meantime our developer couldn't wait for the answer and made it work.
Yesterday we got a message from the vendor that it was not possible to do what we wanted with their product.
When you don't know something is not possible you are open to possibilities.
When someone tells you something is impossible and they are somewhat authoritative, you close your mind to possibilities. Negative input can generate negative outcomes unless you are die-hard "I'll prove you wrong" person.
So don't tell me it is not possible… and even if you do, I might ignore it.
In a somewhat related Post From Seth Godin on Senior Management:
Worth quoting–one of Arthur C. Clarke's lesser known three laws: "When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is probably wrong."