Why shouldn't we think too high of ourselves?
Let's look for the answer in the light of the Word of God:
Romans 12: 3-5 King James Version (NKJV), 3 I say, therefore, by the grace given to me, to all who are among you, who have no higher concept of self than the one that you should have, but think of yourself with sanity, according to the measure of faith that God distributed to each one. 4 Because in the way that in one body we have many members, but not all members have the same function, 5 so that we, being many, are one body in Christ and we are all members of each other.
No one can think too high of himself, simply, because the Bible teaches that human beings are made in the image of God, we must respect the position of each individual under God. This passage does not teach that believers should think of themselves as worthless and insignificant beings, but that no one should consider himself as more worthy, more important, more deserving of salvation, or more essential than any other.
Having different talents does not indicate differences in dignity, because we all belong to one body, and we are all interdependent (Ro 12: 4-5). To think otherwise is to distort reality. Each individual has intrinsic value and dignity, in view of the fact that we are all equal before God and Christ.