I loathe stem and leaf plots.

The only thing more evil, IMO, is the ubiquitous Box and Whisker...

which seems specifically intended to induce confusion about statistical significance and measurement errors later on.

Wait! I think that I have just had an epiphany about why so few people seem to understand what is (or is not) intended with respect to "statistical significance." WOW. Thank you, New Math.

Schrödinger's cat walks into a bar. And doesn't.