No -- I think it's a bad idea to tell someone about how uncomfortable you are in their presence. I think it's best to just stay the hell away from him/her and not waste too much energy with that. If they've already upset you with their actions or inconsideration or whatever (and you have such instense feelings of hatred towards them for it), chances are they don't really care about you and your feelings. Whatever they did was pretty bad and the best thing you can do is stay as far away from that person as possible.
Would you skip your grandmother's funeral if she was nothing but a toad to you when she was alive? If you go to the funeral, you have to run into your self-absorbed, psycho aunt who has also been nothing but a toad to you. Would you skip it, or go?

