Finding a literary agent is like entering a beauty pageant...
and trying to land a modeling contract and vying to be the one the guy picks on that multi-women dating show at the same time. Why? Because it involves strangers making a snap judgment about your worth based on appearance, in this case, the appearance of a three paragraph query letter.
You've spent years pouring your heart, soul, time and creativity into your manuscript, and braved the depths of your high school and college grammar books and thesaurus (yes, the ones you kept in that dusty box in the attic because you knew that someday you'd need them for something) to ensure you've left no grammatical stone unturned. You've joined writing groups, taken online seminars, rounded up beta readers, and agonized over the right word for that sentence. Actually, for most of the sentences.
All of this to be told you have three paragraphs, and sometimes no more than 300 words, to convince a literary agent that your book is worthy of more than the real-life equivalent of an elevator stare. Put another way, those 300 words are your book's dating profile, and it better look smokin' hot if you want to get noticed.
For other writers who have also entered this strange new world, think about this---some of the world's most successful models have glaring "flaws," including large gaps between their teeth, crooked noses, and lots of freckles, which (gasp!), make them "interesting." So query away, be your interesting self, and to quote Tim Allen in that funny movie about a fake starship captain, "Never give up! Never surrender!"