Multi-layered interview, primarily phone screening and aptitude testing. Most interviewers were passionate, energetic, and happy people who all seemed to really believe in the company and like their positions. The final interviewer was disengaged, a bit high-flown, and conducted himself unprofessionally for a final interview (lots of expletives, glugging from water bottles, announced he had other things to do, etc.). I left the final interview feeling confused and deflated. The only explanation was that this was an undisclosed behavioral interview.