I noticed lately that for some reason when friends greet each other here (where I live) they never answer the question of "how are you".
There are two phrases/questions which are generally asked when you greet an aquaintence. "How's it going?" and "How are you?"
Normally "How's it going" is asked first. The person who was greeted responds with "How are you?" The first person who greeted doesn't respond to that question either but just starts a conversation about whatever.

Does that happen where you live?
Are you guilty of not responding with an answer, but with a question instead?
I always found it odd and therefore I'm kind of odd in the sense that I actually answer the person's greeting question and by doing so it throws the greeter out of sync and for a split second they don't know what to do.

I usually greet people with "what's up" or "how's it going" but I guess I'm used to them not answering the question. I usually answer those kinds of questions when asked.

The one that people say here and annoys me is; "alright?" or is it "alright!", are they asking me how am I or telling me how they are or giving their opinion of the situation. People do it with "Okay?" as well "Okay!" Either way a little more effort is required.

Exactly.
It's like people don't really seem to care.
They greet someone out of necessity, I think, because it's the sociable thing to do, but they really couldn't care less how the other person is and just use a phrase or word for greeting so they won't appear rude.

They're getting their "strokes." The mutual greeting gives each of them one, if the other person were to either go into to much detail or not respond things would get awkward. Much of human behavior is motivated by trying to get "strokes", in fact, without them you'd die.

Usually when non-friends say "what's up?" or "how's it going?" (clerks come to mind), I respond with "Hello". On rare occasions I say "Good, and yourself?", but that's in a minority by far.

I get that sometimes too and never understood why. I always answer the question first.

If someone asks how I am, I always respond. If I ask the same question and don't get a response I'll ask again. I'm aggravating that way.

Usually I respond to the question even if they do not expect me to respond.

It's a habit.

I used to respond to questions like that with real answers (how was my day, how I'm feeling) until I picked up that some people just ask this for greeting and not really to ask me a question. It's another way of saying "hi".

So now when I'm asked that, I just say "good, and you?" to get over with the greetings and move to things we really like to talk about.

Of course most of my close friends usually do mean it when they ask - then I give them an honest answer.