Why do you want to learn a language?

The first thing to do is to ask yourself why you want to learn a new language.
Is it just for fun or do you need it for your job? Is it because you fell in love with someone or because you want to go on vacation to a foreign country?
Deciding why you want to learn a language gives you better insight in which way to learn it: a do-it-yourself course or going to a school?