Having natural light streaming into your home is generally good. Not only does it save you on artificial lighting costs, it's also actually good for your well-being. Sunlight helps people from getting depressed, you see.
But what if you don't want the sunlight intruding harshly into your room? What if you don't want to be woken up by its blaring heat on a Saturday morning? And how do you protect your floor and furniture from its rays?
Putting up some well-chosen curtains ought to do the trick. Curtains can minimize the harshness but still let muted light through. Plus, drapes are our friends when we live somewhere where neighbors can easily hear or see us from their own homes.
Just make sure to wash/change those drapes regularly.