It seems that those with the lowest self-esteem appear to have the highest. Usually, this becomes rather clear in the first conversation with the individual. You'll be telling them a story about your weekend or a challenge you're working on in your studies, and no matter what you say, they know a way to "top" it. In a competitive career like mine, it's common to find those that just can't seem to forget that they are the center of the universe. That being said, they expect you to believe they are also the epicenter of your world. If they could learn to put aside this ego, they would not only fair much better in their professional relationships, but also not be so transparent in their quivering confidence.
While confidence is a beautiful thing to have, too much of a good thing is a disaster. We've all been stuck in the conversation with the person who turns everything back to them and how they're so much better than you. PSA: It's annoying. Stop it. Nobody, and I mean nobody, gives a damn about your skinned knee while I'm laying in a hospital bed. They are the kings/queens of making mountains out of molehills (their mountain is bigger than yours, by the way).
So what to do about these egocentric souls? The easy solution is to ignore them. They'll hit their rock bottom eventually and hopefully, build themselves up to be much better (and hopefully, humbler) individuals. What's more, arrogance breeds negativity into the atmosphere. Their ability to belittle you no longer becomes their villainous superpower once they realize that you exude positivity. Overall, Positive Polly will always beat Arrogant Arnold.
You could always try calling them out by taking a verbal pin and pop their overinflated heads. While this can make you some fast enemies, at least you'll have the lasting thought that you did something to improve your situation. Best case scenario, they'll stop talking to you. Worst case scenario, they'll try to ruin your life. But since most people dislike arrogant buttheads, they will fail. So basically, it's a win-win for you either way.
While we love those with bursting confidence and a sense of themselves, it can easily become way too much to handle. It's not easy for them to pocket their egos, as some would need incredibly large pockets, but it is possible to live alongside them peacefully. We're all on the journey of life, and we're all at different steps in this journey. So sit back, eat an ice cream cone, and try your best to squeeze yourself into rooms with large heads.