I was unsuccessful in my interviews with Google several years ago, but left the process more impressed with the company and its employees than when I started. As a candidate, they were incredibly respectful to me, even when it became clear I wasn't the right fit for the roles they needed to fill.

I truly enjoyed them bringing me out for the weekend before my interview so that I wasn't rushed and to give me an opportunity to see the area. I also enjoyed the interview process itself (well, right up until the point one of my interviewers introduced me to some math I had no chance of solving). One of my interviewers even stayed in touch with me after the process, checking in occasionally and helping me make some new contacts.

Today, when I interview people, I keep my Google experience in mind and try to provide candidates a similar impression of my firm.