I'm not saying you should be mean to everyone or not have a heart because others are rude, but we often take things too seriously. It's important to remember your goals when it comes to the nasty world we live in. Sometimes you can only rely on yourself if you don't want to get hurt.
We live in a society where bulling is a constant worry, someone is always trying to one up you and people can be just down right rude. No one says please and thank you, holds the door for strangers or does random acts of kindness anymore. We live in a world where you have to be heartless in order to not get your feelings hurt or get walked all over. It's important to watch your back so it doesn't end up getting stabbed.
I've learned that sometimes you have to be selfish and do what you think is in your best interest and thats okay. The only person that will always have you is you. Always remember what your end goal is because it's easy to get lost along the way. Someone might also be trying to interfere so that goal doesn't happen for you. We are in a society where everything is a competition. Whether it's in the workplace, between companies or being the top in your class. There's always someone or something trying to out do you and be better than you. This is frustrating, but something we all deal with.
In my opinion, you will come across three kinds of people in this world. The ones that care too much, the ones that don't care at all and then the ones that are heartless towards certain subjects. I think being heartless is the best choice because usually someone that is heartless once cared too much at some point. I'd rather put myself first and then worry about everyone else second. I'd rather get hurt and not have it affect me as much. I'd rather be selfish than get walked all over.
A lot of people are heartless because they are damaged or they were taught to be this way. These people are dangerous because they know how to survive in these types of situations. There comes a point in everyone's life where they learn to be heartless in order to protect themselves.