Answer!

Today I'm running pretty close to 自暴自棄, as are some of you apparently (don't give up on ALL people, Clay! Natalie Portman is a person, after all), so first, apologies for missing yesterday. I taught six lessons at Elementary school and then fell asleep until this morning. Second, today I'm short-shafting you, and just giving you Tuesday's answer.

I'm pretty sure "short-shafting" is a mixed metaphor that I just made up... combining "short-shrift" and "shaft" as in "to give someone the shaft." But if "shafting" is bad, shouldn't "short-shafting" be not so bad? I guess my philosophy is that if you're going to do anything, you should do it all the way. If you're going to give or receive the shaft, it might as well be the whole thing. So, sorry for not giving you a thorough enough shafting...

ANSWER:
The actual usage of 海千山千 is negative. A person who has a multitude of different kinds of experience (both good experiences and Dark Side experiences) has the potential, at any time, to be two distinct people. And when dealing with a person like that, you have to be careful, because you never know which dragon you're talking to at any given moment.

例文：彼はちょっと海千山千だから、ご注意してください。
There's something about him that I just don't trust, so please, be careful.

A father's advice to a dating daughter, perhaps?