How unique is God? That may seem like an overly obvious question, but it actually has some very technical aspects that we need to consider before we answer it. I am sure that anyone who believes in God will say that He is unique; no questions asked. Yet, in what way is He unique, and how do we express that quality? Furthermore, we need to ask, how does our view of His uniqueness impact us personally and spiritually?
Mormonism teaches that God is unique in that He is merely greater than us. He is "greater" because He used to be like us, but has evolved and is now better, stronger, and faster (or something like that). Therefore, His uniqueness is matter of quantity--He is "more" than we are. This is heresy; no holds barred, clear, direct heresy. This is why Mormonism is not considered by the Catholic Church to be a genuinely Christian religion. God is not "like us" in this way that Mormonism claims; He never was, never will be, and He does not "evolve" or improve. He is eternal; "with Whom there is no variation or shadow due to change" (James 1:17).
How then, do we understand God? What is the right way to view Him? If His unique nature is not an issue of just being better than us, then what is it? Catholic theology for 2000 years (and Jewish theology before it) has said that God is "wholly other". His uniqueness is due to the fact that He is not a creature; He was never created. He is creator. If we draw a diagram, there is "God" in one area, and there is "creation" in another area; and though the two have interactions, they are not one and the same, nor do they overlap their existence.
Not everything in protestant theology is incorrect. There are many things that they agree with us on (many more than they disagree with us on). I recall something that I learned from a protestant theologian many years before I became Catholic which was a thoroughly Catholic truth. It could be stated simply thus: Creator and creature are two different things, and although Jesus unites us with God there is no sense in which man is to be confused with God. God is "wholly other" Who comes down to us in mercy. We cannot consider Him to be just a big one of us (like Mormonism does). He is truly "foreign" from creation.
All this is to say that God, as close as He comes to us in the person and activity of Christ, is still not a mere creation. He is not a "great-grampa in the sky" Who looks down on us and does what He can to help us out (that is akin to Mormonism, as we said above). Yet, there are many people, even Catholics, who have this view of God. Whatever their reason or intent is for believing this idea, they clearly want Him to be "more like us" than the traditional understanding of God allows.
Recognizing the unique difference of God in theology is important. Recognizing the unique difference of God in our lives, however, is even more important. Little children will not see the importance of this concept, yet we are told to move beyond the doctrinal understanding of children and proceed to maturity. Once we begin to grasp the amazing truth of the "otherness" of God, then we begin to see just how wonderful His grace is. In salvation He is not helping out his "buddies"; He is helping out those whom He created; those who are "foreigners" to His divine nature.
Our recognition of God's unique nature, is directly related to how we speak and write about Him. Do we talk about God like the "big grampa in the sky" (even if we do not believe that He is really like that?). Do we pray to Him like He is a Greek god (hopeful and helpful but not almighty), or do we pray to Him like He is the Sovereign Creator of the universe? There is a radical difference between writing "god" and "God"; they do not have the same meaning. This brings us to the use of language. I once heard a (well meaning) Christian refer to God as the "great big dude in Heaven". This shows a slight bit of respect, but no reverence whatsoever.
Calling God "you" instead of "You" or even "Thou" has an impact on our sense of reverence. Do we capitalize the words that refer to Him, showing that He is different from the rest of us? Our writing reveals whether we see God as just one more of us ("you") or as someone unique ("You")? And if He is unique, then just how unique is He? If He is completely unique, then "You" is not truly sufficient to distinguish Him. Once again, He is not just a "big" one of us. To express Who He is, we would need to go a step further than merely writing "You" and put it as "Thou". It does make a difference in our hearts, even if our modern obsession with "casual-ness" resists it.
This is why some translations of the Bible and many prayers still use the Old English "thee" and "thou" when referring to God. This is also why you will see in some places people still capitalizing the pronouns that refer to God (i.e. "He" rather than "he"). If we are to love Him with all our heart, soul, mind and body, then we have to love Him with our words (written and spoken!). None of us (probably) would pray to God "Hey bud, how's it going?" Not only does it feel wrong, it just sounds crass. How we think about God relates to how we speak about Him, and all of this impacts our love for Him. After all, He made us, not the other way around.