Weird Knocking

So someone knocked on my front door last night at about 10 PM. It’s extremely rare that I feel physically threatened, even more rare inside my own house — threatened enough that I wish I had one or more grenades, rocket launchers, or miniguns at hand, that is — but that was definitely one of those times. Whoever it was didn’t knock again, so I’m assuming they tried the door to see if they could walk in and rob the place, and then moved on. I say that because clearly there could not be any innocent explanation for someone knocking on doors at 10 PM, right? Anyone that knows me even a tiny bit should know that knocking on my door even in broad daylight is unlikely to get a response unless they call first. If someone needed help, they would have kept knocking. I even considered that I might have dreamed it, since I was half-asleep at the time, but my dog also heard it. If whoever knocked on my door happens to be reading this, for the love of God, call me or email me first, unless you *want* to be treated like a hostile threat.