this bitch sucks ... but i suck worse?

So its this cousin I never speak to for some reason, I honestly don't remember the fact why I would ignore her presence whenever I would see her. Family occasions, I would acknowledge all others around her and keep on walking, so in turn she never spoke to me. Today, thanksgiving, I finally spoke ... 'Hi.' I say, she said nothing, 'HI.' I say more forceful, she spoke, yup I made that ... speak. But any who, am I wrong for ignoring her and finally MAKING her speak? Is it normal to not remember why you don't like someone?