Sounds so simple, doesn't it? This is the kind of thing that makes perfect sense in the light of day, sitting in your own living room with your feet on the coffee table. But somehow when you're in that little room across the table from a real live agent, all you can remember is you've got x minutes (8, or 5 or even 3, in some cases) to persuade this person that your book is what he/she wants to see so you have to tell him/her ALL about it. A deer babbling in the headlights is the closest I can come to describing what I call "pitch frenzy." Not a pretty picture, and I know because I've been there.
All that suffering, and I got my agent through the query letter route.