There will be obstacles in the way of understanding each other. You'll have your own set of values and beliefs, which could be incomprehensible to your friend. The ways that you each think and communicate will be alien to each other; you'll feel as if you have little common ground to meet on.
That's not a bad thing in itself, and it's natural to treat unfamiliarity as a threat to the status quo. But you'll both have to put some work in if you want to make this friendship last. The most minor differences in the ways that you think or view the world will get in the way of your communication, so compromise will be needed. You'll have to adjust your minds to see the other's point of view if you want to find any common ground at all. The good news is, this shouldn't be terribly difficult. But you will have to change your own ideas about the way things are in order to allow your new ideas to coexist along with your friend's.