That's why it's so important to watch what you say. To really stop and consider each and every thing that you say and consider the power behind each word. To think before you speak or to do anything that you really want to do. Because sometimes we take for granted that our meaning is clear but sometimes, it isn't. Sometimes, our words and actions can have unintended consequences for sure.
At least, I think people need to take a good look at themselves every once in a while and ask, Is this the person I want to be? Are my actions reflecting who I really am? Am I doing anything that I find cruel and unethical? I think if people did that, did that giving honest answers instead of living in denial (and honestly gave a shit about the answers and what they meant) the world would be a much better place.
Of course, it's easy to let something slip every once in a while. Everyone makes mistakes; it's inevitable. But at least watching what you say can help you understand that you just made a mistake. And to fix those mistakes sooner rather than later.
So many times, people take it for granted that someone understands what they are saying is a joke. Or they won't acknowledge that maybe, just maybe, some part of them really intends to make what they say a jab. So many times people say phrases thoughtlessly, common ones like "Ugh, [something unpleasant] really makes me wanna kill myself" or "Ugh, that's so gay/retarded" or "Oh man, I really got raped in that video game." Never once do these people seem to realize that their comments might actually impact someone near them. It's just stuff like that. Or just thoughtless, bitchy complaints in general."
Sometimes, people even want to hurt someone. They want to insult someone to make themselves feel good. They want to unload on them every once in a while. They say cruel things on purpose but don't realize how actually cruel that they are. They forget how truly hurtful their words are or how they might appear to be hurtful. Or sometimes, it just appears that way and that you really didn't mean what you said (or the person misconstrued your meaning). But it doesn't really matter because you did hurt someone.
So watch what you say. It has meanings far beyond what you might realize.