I'm in your house, workplace, and more.  

Some say I improve the decor.  

To measure me, you measure twice,  

But four times to be more precise.

My pet's known for its speed.  

My best friend's name is Matt.  

I'm usually quite thin,  

But can be rather fat.

The name of my main strength-  

It happens to some food.  

One look at my contents  

Can lighten up your mood.

I endure falls and beatings and bangings.  

I've even been known to survive hangings.  

So spend time with me if you're feeling down.  

I will make a big smile out of that frown.

What am I?

Hint:

> 
>  I am around the things you love.  
> 
>  Bottom, sides, and even above.
> 
> 
>