“Which is more common, words that begin with r (like ‘road’) or words with r as the third letter (like ‘car’)? Most say that words beginning with r are more common. It’s easy to rattle of words beginning with r; harder and slower to free-associate words with r in third place. This is an example of the availability heuristic, and here it leads us astray. Words with r in third place happened to be more common. But because words beginning with r on more mentally available, we overrate how common they are.
A familiar example of availability is the way we all assume that the tastes, politics, education level, and TV viewing habits of our social set are widely shared. We marvel when such-a-such a program is a success or so-and-so gets elected. ‘Nobody would vote for that idiot!’ Well, they did.
Another example: every year, thousands of children aspire to become a professional footballer, despite long odds and near-certain disappointment. Why is that? It’s easy to list names of footballers who beat the odds and became rich and famous. Now try to name some players who tried out for the Premier League and never made it. Can you name any? Hmm, maybe the odds aren’t so bad after all…”
I think that the end of this first paragraph is key: we overate that which is mentally available.