Why is that some people are that disrespectful that almost all of what you do is judge by them unfairly?

i am recently employed in a compony where i am just only more than a month now.. since i had been employed there is this employee which i think hates me? i dnt know if "hate" is the right word which i should use. since she asks my age and knew that where the same age and the youngest of the employees everything i do would have a comment to her or is a big deal which in my part really tearing me apart. once i use a chinese colar blouse then she said laughing pinpointing me which she thought i didnt hear, "lady guard haha!!" (because of the chinese colar)i just didnt said anything but ofcourse i was annoyed, what a disrespect and insult to me right? even anyone would be annoyed as days pes i begun to learn how to defend myself ofcourse i would esp. if i know i had a point..and when i was igned to a new table apart from her, i begun to have a peace in mind and self confidence that im not that person that could just be insulted and just keep quiet and its okay... but 2day i realized