I once went to an interview where they parked me in a conference room and then had various people rotate in to talk with me. I went through several rounds of people, such as HR, the VP of Engineering, then the guy who would be my direct supervisor. As each person left, they went and got the next person on the schedule. In between each conversation, I was left alone in the conference room for a few minutes.
After the third or fourth conversation, I was left in the room by myself again. Time started to go by, and I began to think they had forgotten about me. By this time it was approaching the lunch hour. I waited and waited until after about 45 minutes I finally stuck my head out of the conference room. The surrounding hallways were all darkened and the whole place seemed deserted. I was pretty irritated by that point (especially since the company hadn't really impressed me so far anyway). I think what happened was everyone had gone out to lunch and forgot all about me.
I made the decision to bail and just write them off. I managed to find my way back to the entrance (it was a large 1-story space with a maze of cubicles and offices). I swear the only person left in the office was the receptionist. I dropped off the visitor's badge they had given me (it was a defense company with strict security) and left without a word to the receptionist.
The VP left me an angry voice mail about three hours later, asking why I left and demanding I call him back. What those guys didn't know (and I didn't know at the time either) was that one of my references was that company's biggest customer.
My reference was a former boss that I remained on very good terms with. I had briefly spoken with him prior to the interview to ask him if I could use him as a reference. During that conversation I hadn't revealed the name of the company where I was interviewing. Later that night he called to ask how my interview went. When I recounted my tale of woe and told him the name of the company, he went ballistic. I tried to talk him down because at that point I was ready to just put the whole thing behind me, but he was indignant at how they treated me. Since his company was the prime contractor and their company was the subcontractor he held a lot of power over them.
The next morning I got a series of very apologetic calls from the VP, then the HR lady. They were practically begging for me to come back and complete the interview. At that point I had forgiven them but I still wasn't interested. I politely told the HR lady that first impressions are lasting impressions, and I couldn't shake the thought that if they messed up an interview this badly, what else would they mess up if I came to work for them?
So, always keep in mind that an interview is an opportunity for both candidate and company to put their best foot forward. If a company treats you like this when they're trying to court you, don't believe for a moment that they'll treat you any better as an employee.