The solution to this challenge requires finding the "typos" or misspellings, as clued in by the title.
The typos are as follows:
> Hey there, who are you? Oh no, not another l[i]ttle high handed, self concer[n]ed, wannabe ha[c]ker trying t[o] break my code? Millio[n]s of people have tried and failed. I'm flabbergasted that you'd have the auda[c]ity to k[e]ep try[i]ng, you'll be sorry you ha[v]en’t quit yet! Your be[a]utiful flag has become discom[b]obulated like a[l]l those wannab[e]s who are yet to come!
The missing letters give us the flag: SAH{INCONCEIVABLE}