lab mix continues to get aggressive and destroys blinds, window sills only when left alone.

Question
my lab mix continues to be aggressive by tearing my blinds, tearing up window sills, and the blankets she sleeps on are always messed up like she threw them across the room. she only does this when she is left alone. why does she do it and what can i do in the future to prevent it from happening over and over again?

Answer
That is much more likely boredom and stress than aggression.  What you need to do is crate her.  

It is only natural that a puppy resists its crate at first.  What the puppy
wants more than anything else is to be others, you, anyone else in the
household, and any other pets.  In our modern society, even if we are home,
other things distract us from the attention an uncrated puppy must have.   The
only real solution is to crate the dog when you aren't around.  The dog may be
happier in its den than loose in the house.  It relaxes, it feels safe in its
den.  It rests, the body slows down reducing the need for water and relieving
its self.  Dogs that have been crated all along do very well.  Many of them
will rest in their crates even when the door is open.  I think the plastic
ones give the dog more of a safe, enclosed den feeling.  Metal ones can be put
in a corner or covered with something the dog can't pull in and chew.  Select
a crate just big enough for the full grown dog to stretch out in.

Leave it some toys.  Perhaps a Kong filled with peanut butter.  Don't leave
anything in the crate the dog might chew up.  It will do fine without even any
bedding.  You will come home to a safe dog and a house you can enjoy.

A dog that has not been crated since it was little, may take some work.
Start out just putting its toys and treats in the crate.  Praise it for going
in.  Feed it in the crate.  This is also an easy way to maintain order at
feeding time for more than one dog.

The "shut the puppy in a safe room" is a fallacy.  Very few houses even have a
safe room.  How many of us have a room with a hard surfaced floor and nothing
else?  Most rooms have electrical cords to chew if nothing else.  In addition
to destroying anything a bored puppy finds to chew, it may choke or have
intestinal  blockage from the pieces.  I had a friend that left her dog in a
"safe" room.  It ate a hole in the floor covering.  The safe rooms fail to
give the dog the comfort of the enclosed space their instinct requires.  Nor
do they restrict activity extending the time the dog can go without relieving
itself.