Hands down my worst interview experience was one where I was grilled on exact versions of operating systems, compilers, and software I used. Then over the phone I was asked to implement some simple functions in C++ but the interviewer kept getting annoyed I'd use shorthand like "array of doubles" and wanted me to say it like I was dictating into a compiler! The interview was cut short after I made a few off by one mixups in the code, probably for the best...