duxfemina:

anyone who has a sibling has antagonized someone else, deliberately, for years.

I was the youngest of many children, and had a nephew old enough to be a younger brother, who frequently visited for extended periods. My older brother came up with innumerable ways to antagonize or otherwise mistreat the nephew. Being younger, I naturally went along with it most of the time for many years. Unlike my brother, however, when I could see my nephew was getting upset, I'd usually stop - especially as I got older and developed a more mature world view, and a couple of times I even apologized.

The brother, himself caught in a physchological counterpoint of losing his rights as youngest to me, and having older siblings more powerful than himself, took this position as an excuse to try to rule my life. He intentionally managed to ruin most of the major events of my life, until he went too far and antagonized one of my kids. At this pointed, I called him out on it. He never apologized, but tried to shift blame back to me over an entirely unrelated matter, and has avoided me for the nearly 2 decades since.

His loss. I'm happier this way.