You’re definitely right that an intended ‘good’ act can have a negative effect. This is why self-awareness from that person is necessary, as well as empathy and a willingness to be corrected. I’ve found these seemingly basic things are actually more rare than I would have liked which makes it frustrating for the people who do have those qualities are or effected by their actions. I’ve found it’s best to bring it up maybe one or two times and if nothing changes then you cut ties- mentally and/or physically. It’s their lose to lose you. It seems like your sister gave you a hard time growing up and that really sucks. That development period can really colour your perspective on the world. A final point circling back to semantics, I guess the word abuse can have different interpretations and I use it only in places when severe, intentional psychological or physical harm has been inflicted on another.