I'd like to see people have a clue what a probability actually is. I'm tired of hearing how the weather forecast was "wrong".
Unfortunately my weather forcast doesn't tell me it's between 10 and 15 degrees with 80% probability but the weather forcast for tomorrow is 12 degrees. As such it makes more sense to say it was wrong.
Alternatively, what single concept from statistics would most improve people's interpretations of popular news and daily life events?