Let me bring you into my frame of reference.
From a biological standpoint, when there is less light, your eye receptors pick up on less detail. Thus, picture the day time image of downtown -- the concrete sidewalks are distracted by the marks of graffiti or normal wear and tear, and bits of litter here and there. At night, maybe it's the cool air, showing a more mature side of Houston, but I believe it's really the darkness that lets you see its beauty. As in life, sometimes every detail is too much detail.
The darkness only shows you what's important. The outlines, the broad strokes. Sometimes mother nature gives you no choice for a reason. Imagine that. Before I learned about the biological limitations of our eyes, I thought that the night cityscape was objectively more visually appealing than its daytime counterpart. When I learned it's the limitations our eyes present that create this superior visual, it blew my mind. But instead of thinking that our eyes limit what we see, I re-frame it to say that it shows us exactly what we need to focus on.
I've seen many cities at night. Las Vegas. New York. Houston. Austin. San Francisco. Orlando. Tokyo. Bangkok. Cozumel. Dallas. These images etch in my mind and they give me such inspiration and hope.
For those Houstonites, there's something you must do. Go to the Hilton - Houston (near George R. Brown). Go to the pool deck, and go to the balcony. There's only one pool there, so this shouldn't cause any confusion. It doesn't matter which time you go, but it's preferable to go at night.
One of the most beautiful moments in my life was being on the balcony with one of my best friends, philosophizing about life, at 5 in the morning seeing the dark cityscape of Houston asleep -- and to catch greater and greater detail of the same scenery as Houston awoke. :)