People don't have a good intuitive sense of how to weigh new information in light of what they already know. They tend to overrate it.
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.
