Dictionaries define a mechanical engineer as a person who analyses, designs, produces and maintains mechanical systems using basic physics principles and material technologies; who offers analytical solutions to problems by mathematically modelling physical phenomena and conditions.
If we were asked the same question we would say "people who are busy with making things they know to be possible theoretically."
Why not, if theoretically possible?
We were children who fiddled with everything they found at home in order to understand how it worked. As we grew up to be trained as engineers we understood that what caused machines to work was not the parts, but the idea behind it. This is what is so exciting about it. You can turn anything that science considers theoretically possible into machines.
Today we feel this excitement all over with each new project. Setting out from the wishes, needs or necessities defined by our customers, we produce machines that are capable of giving any shape to any material, be it textile, metal, paper, glass or plastic.
After all this, our most realistic answer to the question WHY? would be CURIOSITY!