Attitude

Why are there so many people who have such a negative attitude? Your attitude is contagious, and I personally want to be around positive people, or at least people who can occassionally laugh or see at least a few good things in their life that they are thankful for. Talking to a negative person (I won't mention any names but this person is close to my age and very closely related to me) is just mentally draining, and you can only try to help a person like this for so long. If that person is unwilling to be helped, it seems like there is nothing you can do except keep trying and risk bringing yourself further and further down by association. If you have never have a problem being positive yourself then by all means, help that other person. However, if you think it could have a drastic effect on your own self, confidence, attitude, life, then is it really worth trying to help such a negative person for years on end?