The devil puts evil thoughts into your head. It's not humans fault, as both God and Satan work in mysterious ways. Just kidding.
"Evil thoughts that are damaging to their own consciousness" is way too vague of a category to even begin talking about it. Both of your criteria there are incredibly subjective. Until you can define your terms more clearly, you might as well be asking what color unicorns shit on Saturn.
I could have evil thoughts/actions that damage others. Example, stealing from a coworker. That damages the victim, not the thief. Unfortunately. Though if I were to do something like that I would feel pretty bad about it. So it would damage me too. EDIT: I'm not sure how to answer the question in the OP...
Well there's fear, that's a damaging emotion fueled by irrational thought. Is it evil? Not really. There are a lot of ways to distort reality, humans are experts at it.
Fear itself is not damaging. On the contrary, fear is life-saving. Excessive fear or fear of mundane things could obviously be considered a negative, but fear itself is not at all irrational or "evil." It's what keeps you from doing things that get you killed lol. Unless of course we're defining "evil" as things that promote life and "good" as things that end it...
I think all humans are half good half evil. They just learn to control their evil half, where others let it loose either on accident or purpose.
I was just wondering about the saying: "to those whom evil is done, do evil in return" I guess to be evil your being evil to yourself first and then onto others. Right? .... I'm high...
I think this is a silly question. Evil itself is just a thought. Is it damaging to understand and know what it is? Of course not. If we didn't, it wouldn't be a concept to begin with and we'd probably be a lot more chaotic.
Well of course, fear keeps us from doing obviously risky things... I was getting at fear can also keep us from achieving our best self, irrational fear. Like fear of change, or letting other people down. Nooo, I do not think we are saying things that keep safe are evil.. that's a bit silly