It’s fine to lose friends. If you don’t, I’m worried for you
Why does society tell you to make up and keep everyone in your life?

It’s true that a fool listens to criticism of his enemies and not his friends. It’s also true that you don’t need to keep poisonous people in your life.
I fell out with a very long term friend recently. He was extremely unpleasant to me, insulting and rude, and while I was shocked and upset at the time, I would still make the same decision now: out out out. I’m used to getting criticised by my friends (while I’m formidable, I usually listen when it counts), but sometimes you need to look at what your friend is saying in context, and why, to work out whether they really care or are just lashing out at you.
The kind of people who enjoy causing you pain or anxiety are the kind of people who will be sadistic when they feel you have hurt them. Whether that’s insulting your appearance, your interests or your actions, if they do it in an insulting and bitter way, particularly when they have not been receiving attention from you, or feel you have slighted them, drop them like a petri dish full of ebola and run. (This goes for boyfriends/girlfriends too.)
These people thrive off you feeling low about yourself so they feel in control. They might well think you are shallow, ugly, stupid, arrogant or boring but if they really cared, they would phrase it in a way that would hurt you as little as possible. If they are nasty about it, they just want you to feel pain and so they can get revenge and feel better about themselves. If I feel a friend is acting badly, I will always try to phrase it in a way that won’t make them feel awful: sandwich it with compliments or insist that they have good qualities, for example. A sadist will just try to rip you for bits.
You don’t need a negative circle around you and you definitely don’t need sadists. People who kick you when they are hurting are people who will leave you at the first hint of a problem.
Obviously, deal with your flaws. Acknowledge them. But don’t put up with people who make you feel awful about yourself because they are upset with you. It’s a vicious cycle: they are hurting so they hurt you, you respond by accepting it, so the pattern continues. Cut ties as soon as you can. These people will never apologise (at least, not for some years) so there is no use trying to form a dialogue on their toxic behaviour.
They might be right. You might well be fat. You could well be dull. You could be a jock. But they are nasty for not taking your feelings or emotions into account, even more so for lashing out because they are hurting.
Often these people will twist reality into their version of events, so they can justify attacking you: maybe you didn’t go to that event with them becomes that you are incredibly selfish and only spend time with them because you are bored. Again, typical tactics of someone who is not in control of their insecurities and have to project them onto other people. Cut. Them. Out.
There will be a gap in your life afterwards but oh my god will you feel better for it. No one deserves to be made to feel unhappy and anxious about themselves all the time by a supposed friend.
Who you are friends with should change: A friend who becomes a threat to you should be ditched. Just because you’ve been friends for a long time doesn’t mean it has to stay that way if they are causing you pain.
In conclusion:
- Acknowledge sadistic, toxic or vengeful behaviour
- Don’t accept bullying from your friends
- Know when it’s time to walk away
- Recognise when criticism is just abuse
- Accept letting go can be for the best