I had a great phone screen with an engineer from the team who was really passionate about the job. When I came in for an interview, almost everyone seemed really excited about the position and engaged—except for one guy who seemed rather disinterested.

I was annoyed that they didn't break for lunch. Pro tip: if the interview starts before noon and ends in the afternoon, provide lunch for the candidate.

What really annoyed me, though, is that I didn't hear back from the recruiter for over a month. I sent a polite thank-you card to the hiring manager and recruiter and expected a little more consideration. I was told they'd get back to me within a week, and it took over a month. At the very least, just check in and let me know that you're looking at a few more candidates before making a decision.

Nothing was particularly difficult. However, the product manager who interviewed me asked some vague, open-ended product design questions—the sort of questions that totally depend on lots of other factors.