Basements confuse me

[Lewis Fisk]

Good evening ladies and gents,

I am confused about basements.  I was hoping that someone could let me in on a couple things.

Like, what makes a basement 'finished' compared to a basement that isn't finished?  

And how much does it cost to finish a basement to a nice finish and when it is finished does it increase the sqft on paper?

Also, as an investor, do you prefer to buy properties that have unfinished or finished and why?

I appreciate anyone's response to anything in this post!

Thank you & Goodnight 

Lewis Fisk @lewisfisk_