Why do we hope to gain? Because when we travel there are so many new experiences so we may hope to learn something new.

What do we hope to gain? New and rare situations, landscapes, cultures, languages to reshape the statue of our mind into something more elaborate. We may hope to be inspired from what we see, whether it be a poor farmer living a happy simple life or dining at a once in a lifetime $2000 dollar dinner.
We hope to gain experience and knowledge in order to later process it and shape a life out of it.