There is a difference between me asking you how to optimize a graph algorithm (good luck--I probably couldn't do that on the fly with references in front of me) vs giving me a basic FizzBuzz.
If I let you pick your language for your FizzBuzz, you need to demonstrate at least some of the following things:
I/O of any flavor (I'll even accept Logging if you don't do standard I/O or console I/O)
String formatting
Modulus Operator
Nested-If statements (or equivalent--Matching, case/switch, etc.)
I'm not looking for production code. I'm looking for 10-20 lines of "A High School senior with a computer class could pass this."
This is not limited to programming, sadly.
I used to have to interview VLSI designers with "Draw me an inverter", and 70% of them couldn't pass.