Well technically, not every mistake is related to grudge but it can be related to some. Example, a teenager just fought with her dad, what would the girl do? She knows she can't speak of for herself since it is "disrespectful." The only thing she can do is to hold on grudge. Later, if she by then remembered her father doings, she might wanted revenge. And soon after it can be like being "childish" or "talking back". Soon after she can realize her own mistake. So yeah, i think grudge is a possible reason.