Well, you could take it either positively if you want to be smart, or negatively if it matters to you to ... um, I don't know, really. I'd take it as a compliment. As for what it means, I think it has to do with the fact that smart people can more readily notice problems, so they have more reasons to worry. Or you can get in trouble for understanding more than some people would want you to.
On the bright side, if you're that smart you should also be able to find your way out.
They're not very smart and typically use cliches instead of generating original phrases.
For this reason, it really doesn't matter what they meant. They're not smart enough for their opinion to mean anything.
It's like being a four year old smart enough to figure out Santa Claus is not real and costing yourself the wonder and excitement of Christmas.
Stop being a cocky ***** or I'll nut ya.
you are too smart for their own good.
waiiiit, that doesn't make sense. basically, you are noticeably smart. maybe tone it down a little-but only if you value and trust this person's opinion.
They are jealous of you being cleverer than them.
they're telling to shut the heck up in a more polite way
I was sad to know that. I knew there should be some hidden meaning, and I found there was. I always tried my best. I helped him figure out that question, but it took time. That sentence was what I got.
It means your own level of "smartness" can and will sooner or later screw you over.
What you know might get you in trouble.
I think it can quite often mean that they cannot think of what to say in reply to something you said.
usually it's in a negative meaning if you know more than you should, and thus you see things whcih shoud remain hidden.