Toxins come in many forms. They can exist as lethal chemicals, naturally-occurring plant substances, or even as human beings. READ ALSO: The 20 Biggest Pet Peeves Every Torontonian Has In psychology, a toxic person is someone who engages in behaviours that impart harmful stress on others. These behaviours can include hateful speech, destructive criticisms, negative sarcasms, threats, belittling, and other actions rooted in bitterness. Toxic people often behave in these manners unintentionally; though, sometimes they may act deliberately and without empathy (because they actually find satisfaction in your discomfort). It's important to avoid toxic people because the stress they create can actually do a significant amount of physical and mental damage to your brain. A study conducted at the Friedrich Schiller University in Germany found that exposure to negative stimuli - like the hateful and violent speech you often come across in the comment sections online - greatly suppresses the activity of your hippocampus, the section of your brain that deals with memory and reasoning. They also found that continued exposure this negative stimuli may cause permanent damage to your brain's neural dendrites, the signal pathways your neurons use to communicate with each other. Deterioration of your brain's dendrites can eventually lead to the destruction of the neurons they're connected to, causing your brain to slowly decay. So you see, avoiding toxic people isn't just necessary for evading drama; it's also necessary for staying healthy in general. Here are 5 types of toxic people you should avoid to make your life better: The Shark Sharks are people who spend every minute of their waking life looking for a fight, whether online or in the real world. They're the type of people to filter through pages and pages of comments just to see which stranger they can pick a fight with next. Instead of just politely correcting your mistakes, they use unnecessary aggression to "teach you a lesson". They will bombard your social media accounts with threats and insults because they have absolutely nothing better to do. They blow things up to unnecessary proportions because they need any excuse to start drama and act stupid. The best way to deal with sharks is to ignore them, as they get too wound up in their own anger to be reasoned with. The Self-Righteous The Self-Righteous are dedicated to emphasizing just how morally superior they are to everyone else. They are quick to point out the flaws in your beliefs and even go as far as to judge you unfairly for them. This narrow-mindedness makes them brutally condescending and almost completely unreceptive to any opinions that do not agree with theirs. Their arrogance is nothing but a false confidence that they use to hide their own insecurities behind. The Puppeteer Puppeteers are master manipulators. To them, friends are for exploiting; not for companionship. They might seem like good friends, but really they're only associating with you because they want something from you. They'll shower you with compliments and tell you what you want to hear, but only if they think that by doing so you'll agree to do their dirty work. The Merciless The Merciless will crucify you for your even your smallest mistakes. Apologies mean nothing to them - they will leave you up on the cross even if your apology is completely genuine and sincere. It's hard to patch things up with them because they take grudges to a whole other level. They get a great sense of fulfillment in making you feel worse about a wrong you've committed, even if you already feel terrible about it. The Crapehanger Crapehangers suck the life out of everyone and everything. They have the uncanny ability to see the negative side of something and amplify it to monstrous degrees. Their utter pessimism and negativity spreads bad vibes even in the most joyous situations, and it seems as if there's absolutely nothing in the world that will make them happy, or nothing that will ever be good enough for them. We're all human. We all make mistakes. We're all just trying to survive. Let's spread love, not hate! Follow us on Snapchat: narcitytoronto