Cindy mentioned "flat", and I agree that seems the main problem. IMO, there's nothing else wrong with the pictures, they are good pictures. But my simple notion is that they are all slightly too dark. A histogram now shows all have slight clipping, but that is predominately the added white Facebook lettering (added as 255). Just slightly more, but nothing significant in the image is that bright. Why not?
This is definitely just my opinion, and was possibly an intentional choice of yours, and we can't really debate personal choices. I'm just stating mine.
I'd make them slightly brighter. It sort of wakes them up.
In the Adobe Levels tool, you do know about the ALT key? Holding ALT key while touching or moving the White Point slider changes the displayed picture (if Preview is On) to show instead only the clipped pixels at that setting (all else is black). Or same thing holding Alt on the Black Point, shows clipping at that end.
Holding the ALT key on the Adobe raw (ACR) Exposure slider does the same thing, shows WHICH pixels are clipped (or the Blacks slider, these are the same Levels tools).
The idea is, some pixels are "don't care" and might be expendable, sometimes.
This view helps you to decide the advantages or disadvantages of clipping slightly. Does it help more than it hurts. Of the clipping indicated, exactly WHICH PIXELS are clipped? Do we care?
I would boost brightness of all of these around 1/3 stop. Maybe a bit more? (esp the third picture.. however that could affect the "mood" you might have been trying to show... ) I think it helps bring all of them to life. In my opinion, it does help these, and yet nothing important in the image suffers, or is even noticeable. Just slight areas of sky or lights or window reflections, where there was no detail anyway. Insignificant.
Specifically, on first picture, I would close that small gap at right end of histogram, and maybe slightly more. Levels with ALT shows this is just some background lights and a bit of featureless sky.
In second, I would close the "almost a gap", to more where the data actually sort of starts.
In third, same thing, but quite a lot more, intentional clipping to where the main data peak actually sort of starts to start.
I would examine that procedure with the ALT key as I went to make sure I wasn't missing something important.
However, it is a fact that LCD monitors straight out of the box tend to be quite bright, which is possibly what you see now? Most of us do. And if so, that is of course how you see and adjust them. But on a calibrated monitor, I think slightly dark.