Indeed, many would envy those in this thread who seem to have avoided having the truly stupid/insane/wicked adults in their lives.
> I was astonished at how much he had learned in seven years.
I actually interpret this as Twain saying that his father was a jerk, but that said father managed to mature with time. But he's written it in a way that the average person would chuckle and say "ah, see, his father wasn't a jerk all along!". Either that, or he's just written a perfect magic mirror.
I think the same kind of quote would absolutely apply in exactly the same way to temperament though. The 14 year old thought his dad was a jerk who mellowed out by the time he was 21, the reality again being that the biggest change was actually the child's temperament.
Always loved that quote.
Unfortunately it doesn't always work out that way. Parents can also get worse as you age and learn that some actions or behaviors are inexcusable. But as a younger person you either didn't understand the context or thought it was okay.