In a way, we all try to be different. But I think we try to be different while still fitting in with a certain group of people so that we won't be so different that we are actually alone. Take for example people who dance. If everyone was a ballerina, it wouldn't be very special. But because everyone isn't, people who dance have a different talent. But dancers automatically fit in with their own group of people who dance. Or people who get lots of tattoos fit in with other people who love tattoo sleeves. People who do crossfit fit in with other people who do crossfit. I've learned well that Physical Therapy students also have their own "differentness." Often, these groups have their own lingo and style that others don't get.
So can we really ever be "different"? I'm not sure. In a sense, I don't think we can. But in another sense, there is no one exactly like us. We are made uniquely by God. We have our own unique thoughts and feelings. These thoughts can lead us to act in a way that makes us irreplaceable to people. We can be parents, leaders, siblings, lovers, friends that are absolutely irreplaceable. To do so we have to be, I think, unselfish. If we bury our head in the sand, doing and thinking only of ourselves, would we really be missed if we were gone?
Most importantly, can our lives be irreplaceable to God? I don't mean to say that ever needs us, but I consider Abraham, who was called the friend of God. Or righteous King David or Paul or the myriads of people who were faithful. God didn't need them, but they were still irreplaceable servants. Let's try to make our service irreplaceable to God!