Attitude

i have seen many people use this word in day to day life.. he/she doesn’t like my attitude or i don't like his/her attitude... some people consider themselves very smart, who decide about someone’s attitude within 5 min. without taking the pains or time to understand the person..
this what i have seen in my life , but i have never taken this word "Attitude" seriously. . because it is not my job to analysis someone else’s character or behaviour..
But today i wish to know more about this and why people use this word, in spite the fact that it hurts quite some people, I also get upset when a person says that you have a bla bla attitude, i dont like it ...i get upset because that very person is not just my good friend but is actually best friend ... so i started pondering about this word and me, I asked myself, am I really bad? ? ?
Attitude: Attitude means one's mental position relative to something - a way of behaving or thinking. . .
But whatever is positive is for someone may be negative to someone else!!
So does that mean, the person has a bad attitude?
I say the answer to that would be no.
I found a very nice one liner, "life is all about 10 percent what happens to us and 90 percent how we react to those happenings."
What if, a person's present reaction is based on his past experience?… imagine, in this situation, someone else judges this person’s current reaction, without knowing the reason behind it…and finally makes up his mind and comments on his attitude… how inconsiderate…
i fail to understand this… how some people tend to judge someone else’s attitude…
this word is complicated, because this word is a sum total of behaviour/ mental setup/ temperament/ likes and dislikes…..
Strange how when our likes match, we tend to have a good attitude and otherwise a bad one in the eyes of a total stranger…..