Some people unfortunately believe that ridicule, cruelty and anger etc... are the best ways to treat people who make a mistake. Their own shame is causing them to project their bad feelings on to you. I know first hand because my dad did that to me. What this does is cause a person to constantly live from a position of lack where they think they are inherently defective and come to expect and accept such bad treatment. But we most certainly do not have to think this way. We are human beings just like everyone else and deserve to see our mistakes as opportunities to be better people in whatever we do. Yes, mistakes are the only way anyone learns. We deserve to be able to set healthy boundaries and when a person says something hurtful, we should kindly tell them it is not ok. We owe that to ourselves as well as them. You can't often change angry, critical people but you can change, over time, how what they say affects you. And you can find friends among the vast multitude of people who are mostly kind and helpful. But just be aware, even truly kind people sometimes make mistakes and act unkind. But they will usually admit to it and eventually apologize. But if we don't speak up and respectfully draw the line, they will never learn from their mistake. And we might unknowingly miss out on a great, trusting and caring friendship.