there are a million reasons for why you find it so terrible.
Which is one of the reasons to why I didn't point out the flaws in the first place.
There is so much you could've done better.
First of all. It seems to me that you've payed NO attention to the ceiling.
If you didn't mind (excuse me) "spamming" the whole floor with prints, I bet it shouldn't been a problem for you to use prints for the ceiling too.
Especially the bathroom is in need of a print ceiling.
You could at least had made some bloody lamps.
At the first look, the walls seem fair nice and you doesn't pay attention to them.
But as a matter of fact, the interior walls are so utterly boring. Mostly because of the wall technique you use.
1x height brick, 5x height wall, 1x height brick. You use the same pattern.
Sure this is okay in some rooms, but you've used it in most of the rooms. I, for example, like the room with one color brown better.
The use of dark brown as bottom and top and then dull light brown in the middle also gives the interior such a flat and boring impression.
The thing I don't like with the furnish is the lack of randomness and "stuff".
You got no material things and details (except the table setting), such as papers, laptops, plants, food and random crap etc.
Some notifications:The black sofa seems too simple for the eye. Try making a new one and it'll maybe turn out better?
The white sofa seems pretty strange to me. It may be some unique style, but it doesn't look so good if the backrest is as fat as the sitting area.
Never use prints for the toilet if you want a quality build.
Bottles are usually not the color of the rainbow and they also should have labels.
I don't like that the glass shelves are full. You should have more randomness and empty spots. This also concerns the bottles.
Candles don't have such flame, I suggest getting some other emitter if you're actually planning on having them lighted.
I would also appreciate some randomness on the candles too. Different length, etc.
Prints on a pool table does not look good in my opinion.
As a conclusion I would say that you need more stuff. The interior seems so empty. Especially the machine room.
Some plants would fit well, too.