How to avoid being played for suckers

In economics, there is a famous "impossible triangle theory", which means that one must understand trade-offs.
A man with the "impossible triangle theory" is handsome, makes money, and is very devoted.
Women "Impossible Triangle Theory" are beautiful, have high IQs, and good personalities.
The "Impossible Triangle Theory" of work: high pay, little work, close to home.
Investment in the "Impossible Triangle Theory" of liquidity, yield, and safety
Remember, no one can play you for suckers.