This quote is encouraging people to think differently. It encourages people to challenge conventional thinking and to think outside the box to make their dreams a reality. The quote is saying that it’s ok to think of creative and innovative ideas. It’s ok to ask why and why not. It’s ok to take risks and push boundaries. This is contrasted to simply looking at things and asking why they exist. Practically speaking, this quote is encouraging people to dream big and to work hard to make their dream a reality.