Here's a thought. Everything we do in life is NOT accepted by the 100%. Meaning, when you feel like you do good, there are still the minority who'll find fault at what you do. Same with negativity. Not everyone will agree with you or sympathize with you and not everyone will curse you. For as long as you are not directing your rants towards a specific person, like harassing or bullying, I don't see anything wrong with posting rant on your personal cyber wall. But when you have someone specific you want to bully on social media, then I suggest you don't do it on your wall. Go directly to that person personally or through private message and settle your rants privately. Remember that when you can't say it to their face, it is not worth posting it. But if you can, do it privately. And on the last note, when you decide to rant on, just be prepared to the comments of the whole world too. Keep in mind that you rant on cyber space to release some tension and not add on more so be ready. Other than that, I don't see any problem posting personal emotions on social media.