What do we mean when we say it today?
When we've heard this out on the streets before, people know they're quoting Shakespeare. It's just got that look and feel to it. Generally, people are going for the whole vengeance is mine thing when this one is trotted out. But without the pillaging and ghost-fighting. It's more the metaphorical power behind the words. Usually.
Don't go blaming us if someone does actually have Ate on speed dial.
Of course, when we say something like "wreak havoc on," we might not know that this phrase has its origins in Shakespeare and the military lingo with which he was familiar. But hey, it means the same thing in the end. See? We're poets and we don't even know it.