How to cut out parts of your life.

"Evaluate your life. Cut out the parts that aren't working." 

How do you cut out people that aren't working? 

Do you say "Oh, I'm sorry but you're kinda a backstabbing bitch and I'm done."? 

Or how about "I think you're wonderful, but I can't take another step forward with you."?

Or maybe "I love you more than anything. But I guess this is it."?

I've evaluated my life. I know what needs to go. But I can't do it. 

How do you tell someone you've loved that you can't be around them anymore? 

How do you tell someone who's friendly to you that you can't take another step in to that friendship with them? 

How do you look at yourself in the mirror and allow the person you see to let go of the most incredible love she has ever experienced?

So I know whats not working. But now what? What do I say?