Internal vs. External Appearance: Do the two relate?

Stated differently: Does someone's personality relate to their external appearance? I feel that personality has nothing to do with external appearance besides a little bit of influence and that any relations are purely coincidence. For instance, when most people look at me for the first time, some find me scary while others find me weird until they get to know me (a big guy wearing dark-ish clothes and usually a tired frown on his face says something about that person). My own personality sort of contrasts with what I wear most of the time. Another thing I'd like to add is that even if personality related to outer appearances, then I'd still give everyone a chance even if they look like we'd hate each other.