Lady Macbeth has always been viewed as an evil woman through and through.  She was the one to come up with the plan to kill Duncan.  She set the time and place.  Then when her husband didn't want to go through with it, she goaded him on. She speaks of bashing out the brains of her own child had she promised him she would.  She would go to such awful lengths to please him and fulfil her promise.

"I have given suck, and know
How tender 'tis to love the babe that milks me:
I would, while it was smiling in my face,
Have pluck'd my nipple from his boneless gums,
And dash'd the brains out, had I so sworn as you
Have done to this."

So she is essentially evil.  The only goodness we might see in her is her love and devotion for her husband and his success.  But she cannot take the guilt that she feels for what he's done (and what she pushed him to do).  So there might be some "goodness" there.  Planning to kill off a king to better her stature (and her husband's) is not being "caught in the wrong situation."  She was calculating and manipulative.  That is her true character.