Why study economics and why is economics interesting?

Many consider that at its heart, economics is a study of
incentives--of what motivates people and companies and nations to do
what they do. That's pretty interesting stuff, really.

Have you read the book FREAKONOMICS? It's by a U. Chicago economist
who uses the tools and techniques of economics to answer more
interesting questions of daily life than one might typically
associated with economics. Might be worth a read...

When it comes to studying a subject, it is important to realize the
opportunity cost involved.  In order to study 1 subject in great
detail, you will be studying other subjects much less.

The marginal returns for spending a year studying economics vs
anything else (ie sociology, physics, theater...) will be somewhat
dependant on your passion for the subject.  The greater the passion,
the greater the returns on your studying.

However, in the long run you must also consider diminishing returns. 
If you spend 10 years studying sociology because it is your passion,
perhaps you could have received better returns had you spent 9 years
studying sociology and 1 year of economics.