I think that too many people often mistake bad relationships for good ones. Sometimes its hard to be alone and we often accept anything just to have someone; because someone is better than no one, right? It's hard to understand what we deserve at times, and that causes us to make decisions to be with people who don't treat us right.
People often fall in love with people that are not suitable for them. They never realize the signs that tell them it isn't meant to be until they're madly in love and they end up broken-hearted when it ends. While every relationship is vastly different, specific toxic signs that tell you it isn't meant to be, stay the same.