Oh - I know this frustration all too well! Conversations I've had with DS6:

me: How was school today?
DS: good
me: What was good? Did you do something you enjoyed?
DS: everything?
me: Anything you didn't like about school?
DS: Yes. Everything.
me: (in my head) Argh!

I get a lot more info asking funny, unexpected questions. Someone sent me this list once:
http://www.huffingtonpost.com/liz-e...m-so-how-was-school-today_b_5738338.html

Asking the one about who he'd switch seats with in class gave me a lot of info about how he sees the other kids, how one kid distracted him by being noisy, etc.

Also, little things can really seem to throw him off. He told me his least favorite part of school was 1st break (they get two 'nutrition' breaks), and this was because the student lunch monitors were breaking a rule about not writing on the white board. Apparently this made him feel 'weird'. He still feels 'weird' about it, even though they don't do this anymore.