I've interviewed for a lot of YC companies and companies that frequently post in the "who's hiring" thread and the programming interviews they give are absolutely horrendous. I've had programming test where companies look at my resume and go "so you are very experienced in Ruby? Great, solve these algorithms in C++ for us. I've actually had someone give me a ACM-ICPC world finals question.

I don't have a problem with pushing someones limits and see where they stumble but a lot of these interviews seem intentionally trying to screw you over with the abstract way these questions are asked and the brain teasers they give you.