Interesting thought from John Bosley:

Your choice of focal length will affect what you see. Would you agree with that? What if I also said that your choice of focal length will affect how you see? That’s a whole different story, now isn’t it? Instead of discussing how focal length affects your view when you look into the viewfinder, I want to talk about how focal length can affect how you look at everything around you before you ever even see it in the viewfinder.

He goes on to make an excellent point. Well worth a read.