Swami Gulagulaananda advised:
"Think not thou art elite, for thy head is below His feet"
In the spiritual or religious sense, it says that you might achieve wonders - But you won't be able to match your glory with that of God.
Here's the practical explanation. Everyone thinks he's the best. But in life, you might have seen that everytime you see someone good, someone better turns up... Sooner or later. If you see a student has scored 96%, someone else has scored 98%, and someone else 100%. But if you think the student with 100% is the best, then you find that he's the topper in his school/college/university. There are thousands of such universities, and someone better might be there; somewhere else. So, we need to remember in life that whatever we achieve is not the ultimate destination - Someone might, if not surely, beat us. So, when we know this to be a fact, being overly proud or vain or haughty serves no purpose. We can also understand the veracity of this statement from "Guinness Book Of World Records" where people keep setting records and someone else is surely going to beat it sooner or later.
Learn to be humble. To have a positive approach is essential. Shun vanity, shun excessive pride, but don't shun pride. Learn to love and respect your achievements.