Irreconcilable differences

Irreconcilable differences are familiar words you see on hollywood divorce papers. It is used so freaking often that its in my mind. Also, the fact that i watch E! news. :p

I always thought that we are all meant to be different or rather unique individuals. How irreconcilable and irreconcilable be? Probably my comprehension of terms and experience is not up to par. Understand me not this.