It's all very well in practice, but it will never work in theory.

An economist is someone who sees something that works in practice and wonders if it would work in theory.

Work relieves us from three great evils, boredom, vice, and want.

Follow the river and you will find the sea

People will ignore their misfortunes and their interests when they are in competition with their pleasures.

An ounce of practice is generally worth more than a ton of theory.