I don't see the link to low self esteem - I see more low self esteem in christians with their endless positivity & smiley faces. Probably something to do with being told they'll never be anything but sinners. A lot of what people negativity is in fact realism.

Sometimes when people are critical, it's a plus because they just gave you an opportunity to agree to deal with the issue.

I usually deal with people's attacks by attacking them back even harder/correcting them/making a joke out of them.

People love to bait aggression to cause problems sometimes, so it becomes necessary to do such things to protect one's self.

I would like to think that a person should consider the affairs of others as a real issue, but everyone already has their own obligations, both social and not social, and that precludes them from such noseing and altruism.

There can be many reasons for it, of course. One would be a lack of empathy; a failure to see a thing from someone else's perspective.

Adorno once said that if you are not worried about life, you are not paying attention. Happy people tend to live their lives with blinkers on. The world is a terrible place; evil, poverty striken, diseased, and most live in desperation.
So at least part of this angst is from people who have taken off the blinkers and are paying attention.
However, many people do not know they are born. They live in comparative luxury, have most of what they need and some of what they want. But this, for some, is not enough and always want more and more.

Well if I can I try to bring a little pep to their day but if they refuse to be pepped up..Well not much for me to do but go on with my day.

I assume they are suffering and give them a wide berth.

years ago SNL had a skit called the , "Miss Self Esteem Contest"

I surround myself with positive people. The ears are an orifice, just like the eyes and mouth. We can choose what we take in.

Ten years ago, I told an old friend that her constant complaining and negative talk was dragging me down. I asked her to be be more positive around me. She hasn't spoken to me since.

That was her choice. She loves to play victim.

"Perhaps the road has been too long, and the night too lonely"

It is usually a means which such a person seeks to establish dominance and control. Control is the driving motive in such a person's life.Such behavior is one of the symptoms of a borderline personality disorder. If it is a case of borderline personality disorder, GET AWAY from that person and stay away from them, or they will damage -- if not ruin -- your life.

I tell them to chill out.
If it persists, the don't stay in my acquaintance for long.
I don't suffer overly negative people well.

There are just some people who are not happy unless they have something to be unhappy about

For some of us it's our personality. I'm a critical and bitter person by nature. Imagine how we feel dealing with you bright side people. It's not fun for us either.