Progressive U Creative Writing

Easily mistaken-
Easily confused-
Me and my family,
can keep you amused.

Now, some places I am an only "child",
and in others,
there's so many finding us might take a while.

We can hide in the most complicated places,
and when you use me,
You are bound to see many faces.

Sometimes, I even decide to behave,
and where you leave me,
is where I lay.

Making decisions is what I do best,
I can change the faces you see,
Put me to the test!

Can you solve my riddle?
-so disguised?
Guess what I am...
You might be surprised!