Difference between these two phrases?

Difference between these two phrases?
 

Hi, why is one of these phrases subjunctive and the other inductive? Thanks if someone could explain.

Quisiera dos libros, por favor.
Quiero dos libros, por favor.

Thanks, saludos.

Quisiera is polite and tentitive.
Quiero is direct and can sound blunt depending on the circumstances.

I would like two books (similar to quisiera).
I want two books (quiero).

It's the same difference as between

I would like two books, please
I want two books, please.

Except that the second one in Spanish is not as impolite as the English.

By the way, please stop saying 'phrase' when you mean sentence. A phrase has no finite verb in it, so "why is one of these phrases subjunctive and the other inductive" is meaningless. And you mean indicative, not inductive. :)

Edit: Poli beat me to it!