It's not easy.

As we grow, we will slowly learn what is manners and how to respect each others. We cannot always just think for ourselves only but for others too. Besides that, we have to think properly before we talk something because our words always the one that hurt people most. Even though that person might not show any react but doesn't mean your words didn't hurt that person. Try to imagine that you're the one who heard those words and how will you react ? It's same for everyone. We're human and human have feelings, except you're not human. Lol ! When we respect a person, we expect he/she to respect back but not everyone can make it. This so called Reality ! Reality is always cruel.