Meta PM interview questions

I was contacted by a recruiter, and scheduled an interview. I wasn't sure about it but it seemed foolish not even to talk to Facebook. Invited to the new Menlo Park campus for two in-person interview with two different PMs. One interview focused on improvements and product ideas for Facebook. The interviewers were both very pleasant to talk to, and pushed every idea I'd come up with further, asking questions like "What are the potential drawbacks of that?" or "How would you integrate that with X other feature on Facebook?" The other focused on logic and estimation problems, seeing if I could come up with a reasonable method for estimating impossible-to-nail values. This was pretty fun, actually, and I think went pretty well. In the end, I received an email rejection after following up a few days later with a vague statement about how I could have had better vision -- reading between the lines, I hadn't done my homework in advance on the current cutting-edge developments at Facebook. Still a very positive experience, and the two PMs I talked to were genuine, friendly, and enthusiastic about the process and any questions I had.

1 day phone interview, 2 days on-site prepared ideas/sketches for new product ideas some interviewers were open/willing to listen to background & ideas, while others seemed disinterested and had their own point of view to push background or experience is NOT valued reviewed, in-depth current product offering and suggested improvements, but it never came off as valuable to them, just whether or not it fit with the Facebook stance