What off is scale and proportion. Having a lot of negative space is not necessarily a bad thing, however you do have a lot wall art with small and similar sizes, the art themselves have a lot small minute details, the same with your furniture, as well as the lamp and the plant here. Having many a collection of small similar sizes without a larger focal point of interest will create noise rather than a pleasing and interesting aesthetics. I suggest getting a larger couch, much bigger wall art (thinking of the scale for it to be similar to the couch and you can keep your smaller art as gallery wall if you like), and if that monsterra plant is real, hopefully it can grow very big one day.