We are similar because our DNA is extremely diversified when it comes to our facial features, making our faces much more distinct from others. Studies have found that since before the age of the modern man, it is quite probable that our DNA has been tilted in support of the definition of individuals based on the details of the head and face. Through evolution, traits that would threaten the life of the individual either died out or changed. Traits that were not negative, allowed for greater diversity in combination with all of the features of the face. This makes it easier for us to recognize one another as we are completely unique, but it's also really fascinating to know that it's a human trait to have highly-complex facial makeup DNA.
Humans. Individuals. Cool.