The job description Bezos wrote for his very first employee said, “You must have experience designing and building large and complex (yet maintainable) systems, and you should be able to do so in about one-third the time that most competent people think possible.
Have become a huge fan of @mattmochary 's idea of checking your energy level before and after chatting with someone, when deciding whether to work with them.
It seems a bit silly when you first hear about it, but over time it's become my #1 most important hiring heuristic.