If you're looking at a magic eye picture correctly, and you very slowly rotate the image around an axis perpendicular to itself (i.e. rotate the image like it's a stearing wheel), then your eyeballs feel like they're being pulled out of their sockets a little. Is there a name for this effect? How does it work?
It's hard to get people to rsvp "no" to something, making headcounts difficult. Wanabe evite successors should think about how to incentivize an actual decision from invitees.