Why is "being created" considered an imperfection?

I've seen the uncreated God contrasted many times to the created angels, Satan, and humans, and etc. Being created is counted against the latter category as a mark of imperfection which God does not bear. However I don't really see why being created is an imperfection. Surely something can be created and be created perfectly, right? To become perfect? Is there a way to understand this through the bigger picture of what perfection is? Or is this something that must be understood on its own?