Around the Fire with D. V. Stone-What's Behind That Door?

The following quotes are from my WIP Kingdom at a Crossroad. These words have not changed since putting the proverbial pen to paper way back in 2015. 

"All beings, if they are noble of character, will do the correct thing whether or not they have hope in their hearts."
Tuilelaith to Kíeran

“That is the problem with the good. They don’t understand pure evil. They always think there is hope. You, my dear are the proof they are wrong.”
Dalbhach to Ceara

I have been doing a lot of work on Aimhirghin recently. My first book baby is still a work in progress and recently turning circumspect with it, asking what my motivation is, what are my character's motivations? These questions lead to considering the deeper thoughts of life.
Or staring into the heart things
A critique partners once made the following statement.
I struggled a bit with the Wizard Athair. I struggled to determine whether he was a good guy or a bad guy. I think he’s good, but I’m not sure. 
Good observation! Many of my characters have that question asked about them throughout. Mostly in Athair and Sárnait, but everyone gets a turn in the frying pan. It is a bit of my 'philosophy'. I don't believe anyone is all good. We all have something in us. We choose to act or not on  on those thoughts, impulses and desires, hence Tuilelaith's words on nobility. Some are just better than others at wearing a mask like Sárnait.
I have been taking my characters apart and looking into their hearts, examining the good, the bad, and the really bad. At some point, every character has to make a choice. Some choices are tougher than others. And sometimes even the good characters make the wrong choice.
Why did they do that? My answer? It's because I may have done the same thing. 
Every character in my manuscripts have a piece of me, and who I am, in them. And sometimes I just want to dope-slap myself for having certain thoughts. Usually in traffic. Have you been to New Jersey?

I like this picture. I see the heart. But what's behind that door?

​Recently there has been a growing trope in books regarding the "morally gray" character, though these characters have been around for a while. Think Batman, Severus Snape, Lord Varys, Boromir, and Celaena Sardothien to name a few. I might add Liam Neeson in the Taken movies he's breaking laws left and right even for a good reason. 
So, like this door, the morally gray may look like love on the outside, but yank on the handle and you may find Tony Stark.
What are your thoughts? Who are some morally gray characters? What makes them that?