* I applied for both APM and dev, and chose the APM route after passing first round for both.
What I found insulting was the lack of communication, complete disregard for my time, and general attitude of the HR people. It shouldn't take three weeks to let me know if I passed an interview, for an internship, when I tell you I'm under time pressure. I had an exploding offer from Microsoft, which they graciously extended so I could keep interviewing with their rival, and Google still took their sweet time. I was told I couldn't write the essay until they'd decided I'd passed the second round interview, even though it would have cost them nothing to let me write it and then throw it out if they decided I hadn't passed the interview. And when I turned it in, I was told it had to be "reviewed by the hiring committee, which meets every Friday, but they're not going to look at it this Friday, you'll have to wait a week and a half." When I basically told them that I wasn't going to let my other offer expire, they begrudgingly looked at it that week, but they made it very clear they weren't happy about doing me the "favor".
As someone else said, Google gives the impression of being full of huge egos who think that everyone is just dying to work for them, and that working anywhere else is a distant second choice. It's arrogant and egotistical. Think that if you want (even though it's not true, at least among Stanford CS students), but it shouldn't come off so blatantly to potential recruits.
Edit: timr just reminded me of something else - the interviewers seem trained to emanate disinterest. They were the least friendly interviewers I've ever had. And like I said, Google seemed at least a bit interested in me, since I got through both rounds of interviews, so I doubt it was personal.