Why a linked list always come between me and a great job offer

Recently I interviewed at a big company in bay area and everything went well except I can't FINISH (but explain the approach and half coding done) coding a version of reverse a linked list in 20 minutes. I am coding in java for last 4+ years. Why all of my great work experience and coding and design skills + good performance in other 4.5 interviews are escaped by a single linked list question?? Is this the trend in all over bay area technology companies????