Disclaimer: If you are a former friend of mine who I have distanced myself from, I am not calling you out. I'm not calling you a bad person. I'm not even calling you a bad friend. We just were not good for each other.
Have you ever had a friend who, despite being a genuinely good and fun person, you actively avoided because every time you saw them you automatically felt envious/competitive/insecure etc? I know I definitely have. And truly, I still feel guilty thinking about them because that situation is completely out of their control.
A toxic friendship is one where some aspect of the relationship is detrimental to your emotional and mental health. In some cases, people are genuinely mean, manipulative, and intentionally demeaning towards their "friends". This is clearly a toxic friendship, but that's not the type of situation I'm discussing today.
What I'm writing about are friendships that theoretically should work out: both people are respectful, supportive, mature, and caring. They enjoy each other's company, maybe share some interests or hobbies, and are generally agreeable. The only thing that stops this friendship from being a healthy, functioning one is a typically subconscious undercurrent of tension.
The source of this tension isn't necessarily identifiable, and sometimes, there is no rational reason. It could stem from mutual insecurities, differences in how things are perceived, or competitiveness. These types of problems seem like they should be easy to fix, and oftentimes they are. Sometimes, however, people are at points in their lives where they cannot change or do not want to change, and so the tension continues to exist.
Constant tension puts a lot of pressure on a friendship, obviously, and it's easy for the relationship to begin to feel like a burden. Friends are supposed to be a source of comfort and support for one another, and when relations are strained, you lose that vital aspect of friendship. Soon, both friends are stuck feeling trapped in a relationship that drains them emotionally.
The thing about toxic friendships is that ending one can feel like a personal attack on the friend being "dumped". What a lot of people don't realize in the moment is that the individuals in the friendship aren't necessarily toxic themselves. It is the way their personalities intersect that creates the toxicity.
Sometimes, people just clash. Not in an aggressive way, not in an intentional way, not even always in an apparent way. For example, an old friend and I were similar in almost every way, we had fun together, and we shared all of our problems with one another. I loved her, but I was also very insecure around her. We were both perfectionists, we were both intelligent, and we were both extremely competitive. None of these qualities are necessarily bad, but they made it difficult to be close to one another without everything turning into a competition. These aren't qualities you can change overnight, or even at all in some cases, so our friendship continued to grow more strained as we continually compared and pitted ourselves against one another. It wasn't explicit competition and it was never discussed, but we could both feel how it shifted our relationship
Neither of us was bad people, and she was one of my closest friends. Eventually, I had to remove myself from the friendship though, because I recognized how it was hurting me. It created insecurities that I had not gone into the friendship with, and it was exhausting trying to keep up with or be better than her all the time. I didn't blame her, but I also knew that we weren't helping each other grow.
Of the friends I have had to stop being friends with, if I met them for the first time today, I would probably be able to have a healthy relationship with them, simply because I am in a much more secure and stable point in my life. Things that caused issues to arise in previous friendships are no longer significant because I have changed as a person.
Long story short; you're not a bad person for leaving a toxic friend, you're not a bad person for having been a toxic friend, and you're not a bad friend. You just, at that given point in time, were not suited to one another. It's okay.