Don't you just hate it when people consider something that you know how to do as "really cool", except with a different person?
For example, my roommate said something like "It was really cool... he even used LaTeX! ", implying that LaTeX was some sort of hard, pain-in-the-ass-to-learn programming language. Well, I know LaTeX. So I said to him, "Doesn't everyone?".
This serves two purposes. Usually when someone makes a stupid comment like that, you want to say "Yeah! Well I know LaTeX too! I use it for all my papers!", but then you sound arrogant. But not saying something makes you (well, me anyway) mad. So the perfect target for an insult is the speaker. My roommate doesn't know LaTeX, so by saying that everyone knows LaTeX, you imply that he is stupid. Rather than raising yourself above the speaker, you lower him. So in the end, you win
So my point is this: to come out on top (whatever that means) in a conversation where someone is impressed by another party's skills that you also posess, the perfect response is "Can't everyone do that?". You don't sound arrogant by elevating yourself above the speaker. Rather, you lower him to a level below everyone else. So you end up "winning".
It's really pretty interesting if you think about it. Try it out. But no comments that claims that everyone knows this. If they did they would have posted it in their journal because it's so cool