When you visit a new country, it's helpful to anticipate what it's going to be like. Otherwise, you may end up with a case of culture shock that'll paralyze you mentally (and emotionally) until you're on the plane ride home.
Why you should overcome barriers
A large part of an effective mission trip is embracing the community and culture as they are. If you're taken back and completely "shocked" by the smells, customs, and food, you'll be less likely to embrace the people and their community.