In one sentence, describe what the following article is about:

It can be tough to recognize when someone is toxic and not in your best interest, especially if it’s someone you’ve known a while. One sure sign of a toxic, negative person is listening to your gut and how they make you feel.  You may dread being around them and exhibit signs of nervousness anticipating meetings like sweat palms, nausea and a general uneasy feeling. Toxic, negative people tend to exude pessimism and can even be physically or verbally abusive. If you find any of these traits in your relationship with a family member or friend, you may need to evaluate the relationship. People who are negative and toxic tend to have one-sided relationships. Sometimes it can be hard to be an observer of your own relationship. Watch how they interact with their other friends, particularly whether they talk negatively about other people. Those who feel the need to bring others down may do the same to you. They always worry about themselves. Whether you’re telling them about your day or your own feelings, toxic people will turn the focus to themselves. They also tend to be greedy and more concerned with their wellbeing than yours. When you realize that someone dislikes you and you’d be better off without his or her negativity, make a change for your own good. This important step means you’re ready to seek positive change in your life and surround yourself with people of similar goals.

Summary:
Focus on how they make you feel. Observe their other relationships. Realize you need a change.