Venous thromboembolism.
Had my DNA scanned, and I noted that their average lifetime risk for this was 12%, which is pretty high for a life threatening condition.
I'm at 12.8% risk for venous thromboembolism and the average (for "men of European ethnicity") is 12.3%.
As everyone here knows, it would be a stupid idea to switch from airplanes to cars out of safety/terrorism concerns: Cars are a much more risky means of transportation than airplanes. But what other major risks are there that many people systematically undervalue or are not even consciously aware of?
The same can be asked for chances.