Well, if they did, then it turned out to be good advice (or it was a good rule, depending how things ran in your house!).
Gretchen Rubin, author of The Happiness Project, turned me on to this idea, and now that she has, it makes perfect sense.
If you're like most people, when you get out of the bed and stroll to the kitchen to get the coffee brewing (or whatever you do first), you leave the bed sheets in a disheveled mess. You might pass them by on your way to the shower, and again on your way to the closet to get dressed. And then you grab your stuff and head out the door. Most people just don't make their bed.
But productivity experts always tout the value of achieving small tasks at the start of each day in order to prime the pump for accomplishing larger ones later in the day.
That logic can be extrapolated into the bedroom, where with only a few minutes you can sort and place the jumbled blankets into their proper place - spread neatly across the bed. The benefits are two-fold: you have accomplished a small task that sets you up for a productive day, and you have an aesthetically pleasing place to return at the end of your day.
Somebody (I'm not sure who) has put together some great visuals that contrast people who make their beds with those who don't. Those are worth your time to check out.
So it seems that our parents were right: making your bed each day is a good habit to form.
If you need help with how to make your bed, maybe this video will help:
Are You Well?
Action & Attention (Working Out & Eating Well)