Project minions often have a misconception about requirements gathering: that it's a one time deal. An analyst goes to the client, has a sit down with donuts and coffee, and leaves a few hours later with a laundry list of items for people to code/skin/write charge lines for.
It's more like going to the grocery store with a hyperactive significant other.
"Okay. We're here to shop for Thanksgiving. What do we need?"
"Is this going to take very long? Because the game's coming on, and..."
"I'll make it as quick as possible. First on our list: the main dish. I was thinking--"
"Can't we start with dessert? That's more fun."
"It's at the other end of the store. Anyway, we should pick out the turkey and ham first, right?"
"Sigh. Fine. That one and that one."
"Are you sure, because I don't think the turkey will be big enough to feed--"
"What are you talking about!? It's HUGE! So, desserts."
"Sigh. No, now we do sides. Here's a list of recommended sides."
"Wow... that's a lot of sides. Why do we have to have so many?"
"Because people like them, and hundreds of Thanksgivings have shown us that this is a good standard load."
"Feh. Halve it. We can spend what we save on pie."
"Fine. Whatever. You get to explain that decision to grandma. Now for drinks..."
"Okay! Okay! Pie! Go get your pies and then we can talk drinks."
"That is WAY too much pie. That's nearly our whole budget!"
"But... but... Carl has this pie at his dinner, and Jennie has this pie at her dinner, and Lisel has CAKE, and this one..."
"Just because someone else has it doesn't mean you have to have it!"
"Sigh. Fine. We'll have turkey and pie. But you get to tell everyone why."
"Everyone will love it. You just wait and see."
There are very few people who love turkey and pie, exclusively.
This is what gathering requirements is like to me, when I try to do it in one sit down. There are, of course, alternatives. Those, next time.
Note: Before the world thinks that I'm portraying my SO, I would just like everyone to know that my darling husband grocery shops like someone has leaked poisonous gas into the store. He is, however, prone to sneaking Pop-ums into the cart when I'm not looking.