To be "too smart by half" (also common is "too clever by half") is to be too smart for one's own good, meant either literally or ironically. As an idiom, it is usually sarcastic. The phrase has a wide range of potential uses; for instance, it can mean:
1.) Something so complex that it's self-obfuscating.
2.) A seemingly clever action that is in fact foolish.
3.) Logically accepting something as necessary that isn't.
4.) Overanalysis.
5.) Elitism (see ivory tower).
Caused by overworking the Central nervous system of the brain. Eventually certain parts of the body start to shut down, usually starting with the left foot and working its way up the body. Although T.S.D. is very rare, there have been 37 recorded deaths.
Stephen Hawkings is the most well known person who suffers from T.S.D. (Too smart Disease) Another well know case was FranklinRoosevelt
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.
A lighthearted reaction upon receiving disappointing news of some sort. Usually something that isn't a particularly a big deal, esp. when it primarily affects someone else - sort of a mild schadenfreude. Sometimes doubled or tripled, and possibly said in a sing-songy voice for added comedic effect to imitate a muted trumpet, which is how the meme originated.