I applied for the position via LinkedIn and was contacted by an internal recruiter for an initial phone screen (~45 min), which went fine. The next level was a phone interview conducted by the actual hiring manager (~1 hour). Typical background questions were asked as they applied to the position and there were no questions out of the ordinary. Next level interview was a F2F interview with the hiring manager and the company's managing partners on-site. This is where things went south and in my opinion, very unprofessional. I arrived promptly for my interview (9:30am), but waited for 20 min in an empty conference room for my first interviewer. First interviewer was one of the managing partners and the conversation flowed well. I subsequently waited for another 30 minutes for my next interviewer to arrive and eventually had to ask the receptionist if anyone was going to come talk with me. After waiting another 10 minutes, someone did finally come talk with me, although briefly. I waited yet another 20 minutes for the hiring manager and other managing partner to arrive. Interview with them went fine and finished off the interview process talking with a potential colleague. I left their office at 1:40pm. First, never in my 17 years of professional experience have I seen or heard of anything like this happening to a potential job candidate. Second, it never dawned on anyone that I was there from 9:30 am to 1:40 pm without an offer to go to lunch to finish the interview process. Needless to say I was stunned. For the first time in my career I almost walked out of an interview, but came to my senses.