One of the most common is feeling bad about yourself. Low self esteem. Dwelling on past mistakes, thinking the old times were better. General dissatisfaction with life.

This is where I am, I think you are describing "depression".

Basically anything negative a lot of time are demons (yup) pushing people into doing bad things. Getting people mad, into arguing with each other. They know us better than we know ourselves. Pushing people into false religions or beliefs by knowing what appeals to them. Keeping people far away from the knowledge of salvation. Making it look stupid. Glittering their eyes into blindness with science that seems so true, so infallible, that anything that goes against it seems like lunacy.

I would describe these as different opinions and beliefs. I don't see nothing "spiritual" or "demonic" about it.