Susan (thanks, hon!) asked about opening with dialogue.
Starting with dialogue was a trend from a few years back-- I do remember trying to force a dialogue opening!
But generally, frankly (you do want me to be frank, right? You know, my husband's an attorney, and so is Theresa, and I don't know about Theresa, but the dh says that anyone who says "frankly" isn't going to be frank, and if an attorney says, "Trust me," you should run the other way, and I'm ALWAYS saying, "Trust me!" So maybe we should let Theresa say whether you should trust me!) what was I saying? I forget.
Oh, yeah, dialogue to start a story. Well, I'm always willing to be swayed by wonderfulness, but generally, I am not interested in a dialogue start. Sure, if it's wonderful dialogue-- I'm reminded of a Buffy episode opening, where Giles's lovely voice was going on and on about how he couldn't believe Buffy the Vampire Slayer had joined a cult, and it's such a terrible cult-- and then the camera cuts to Buffy, and she's wearing a cheerleader outfit. (Cheerleader=cult in Giles's mind, see?)
That's a good dialogue opening. But trust me (eek!)... most of the dialogue openings I've read are NOT intriguing, though they might be if read by Giles. (I love Giles.)
What's the prob with a dialogue opening?
Well, if it's generic enough that we understand who is saying this and what this is about, it's too generic to start YOUR book.
And if it's not generic, and we don't understand it, are you risking losing us to confusion in the first sentence?
Dialogue openings can work... but I'd say if you want to go it that way, hook it to a tag that tells us who is saying this. Please.
But then, if it works, it works. It's just that so far, it hasn't tended to work for me... it's a low-percentage opening, in my experience. But if it's actually right for your book, go for it! Just consider adding a quote tag that tells us who said that and why or how or something.