One sentence or less
I personally believe every topic should be explainable in one sentence or less.  For example,
Mechanical Engineering - The study and application of position, velocity, and acceleration to determine the forces and moments acting on an object.

Christianity - The religion that emphasizes personal salvation through the sacrifice of Jesus Christ as a means of accessing and drawing closer to the God of heaven and earth.

Rocket Science - The study of objects in flight assisted by an active propelling force.
See?  Simple.  Whenever I need to ask a long talker to explain something, I usually specify to do it in one sentence or less.  If they can't, they're not trying hard enough.  If they don't, I don't listen. #language

Flying over water
I have a fear of flying over bodies of water because if the plane crashed, I would need to find something to float on so I could paddle back to shore.  But after thinking about it for two seconds, I realized that a plane has about an equal chance of surviving a crash on water as on land, i.e. the plane would disintegrate on impact.  And despite what TV shows like Lost have taught us about plane crashes, most of them end in the death of everyone on board. 

So that should make me feel better about flying over bodies of water.  Yeah. #travel