There's always the risk that there are unknown unknowns.

You can build a statistical model and that's all well and good, but if you're dealing with a new type of financial instrument, for example, or a new type of situation - then the choices you're making are pretty arbitrary in a lot of respects.

You get steely nerves playing poker.

If you aren't taking a representative sample, you won't get a representative snapshot.

I prefer more to kind of show people different things than tell them 'oh, here's what you should believe' and, over time, you can build up a rapport with your audience.