I get a lot of opening lines like this: "Have you ever wondered if everyone around you is a flesh eating zombie, only they have developed supernatural powers to seem like actual people but when they're talking to you they're actually sizing you up to see if you would taste good?" Why, yes, clearly. I mean, who doesn't wonder if everyone around you is a flesh eating zombie sizing you up for dinner. In fact, I was just thinking that.
Do not use rhetorical questions in your query letters. Not only do they reflect lazy writing and beg a negative response ("Nope, I don't wonder about that"), they make your book sound hopelessly mundane. Just look how some great works of literature wither under the dark power of the rhetorical question:
"Have you ever wondered what would happen if you joined a whaling ship, only it was piloted by this guy who wasn't really into whaling but he mostly wanted to just go after a white whale?" (Moby Dick)
"Have you ever had a day where you just wanted to take a moment and think about a lot of things?" (Ulysses)
"Did you ever just want to get away from it all?" (Robinson Crusoe)
Rhetorical questions are a powerful force for evil. They feel no pain and can't be reasoned with. Do I wish rhetorical questions would temporarily assume human form so I could tell Mr. Rhetorical Question that he is bad writing and should never allow himself to be used in any letters, particularly ones addressed to me because they are a sure-fire sign of a query letter gone astray and I will probably not want to request a manuscript if he is in the letter? Yes. Yes, I do.