Co worker problem I work with someone for almost 8 yrs & she is nasty?

No one is perfect I see my own faults as well Most people will mention to one another how the person is ( direct confrontation doesn't work it has been tried) It makes the work environment stressful& brings the whole mood of the place down when she is there ( kind of like a bully in high school) I have heard that when people are like this they must be unhappy somewhere in there own life & must have an unconscious need to bring others down ( people are not born nasty something has to make them that way) I say prayers for this women & for the wisdom to get through every day I would like to maybe write her a card ( I feel bad for her people say I am crazy for that) I do not know what to say & I don't want to open a can of worms with a card either ( she would never admit to anything wrong in her life (or would tell you to mind your own business) I just want to write her something to diffuse the tension in the office any one have any ideas on what they would say I am not the most eloquent writer in the world ( only serious answers please no one telling me to tell her off or be nasty back( I work in an office & want thing better not worse)thanks for you input