I can' t speak for everyone but I believe the reason that we hunters mount our animals is to remind us and never let us forget the memories that we made when we hunted and took that animal.
I know when someone has an animal mounted and I see it for the first time, I always ask, " tell me the story behind that one." We want to hear the stories, we want to remember the hunt.
My great grandfather took a great muley buck along time ago. He got it mounted and I remember growing up as a little kid seeing this monster muley hanging on his wall. I never got to hear the story of how he took that buck. After he passed away back in 1993, my dad got the mount and it now hangs in the garage at his house. The mount is in bad shape, the hair is falling out, the hide on the nose is split, and the left ear is broken and about to fall off. Everytime I look at that monster buck hangin there on the wall, I wonder what story my great-grandpa would have told me about that hunt and what memories he made the day he got that bruiser. To me, that' s why we display those animals on the wall.